I do blacksmithing as a hobby so I think I will chime in.
A real sword has 4 parts. The first and obviously most important part is the blade. The blade runs then entire length of the sword from the blade down to where it turns into the tang and a little bit further.
The material it is made of determines a lot about the blade. Steel comes in many varying alloys (there are literally hundreds, if not thousands). The most basic steel alloy is a mixture of iron and carbon, which is steel. The carbon and iron form a crystalline matrix which is what gives steel it's strength. Your basic steel you buy from like Lowe's or Home Depot is usually something low carbon like 1018, which is .18% carbon and 99.82% iron (by mass). A file for instance, which is used to shape metal, can be upwards of .9% to 1.2% depending on the alloy.
The more carbon, the harder the steel is. This is measured on the Rockwell C scale (typically, there are multiple scaling conventions). A typical file could be upwards to RC 65 depending on the alloy. A tungsten carbide alloy is upwards of RC 85 (this is what is used to machine hard metals typically).
The hardness is a result of carbon content and the heat treating process, which is probably the MOST crucial process of making a blade. It, along with alloy, determines EVERYTHING about the blade and it is all about trade offs. The harder your make the metal, the better it will hold its edge but the more brittle it will be. The tougher (less brittle) you make it, the worse it will hold its' edge. I've shown many people that i can break a piece of steel with my bare hands
There are 4 heat treatment processes: annealing, normalizing, quenching, tempering. The first 3 involve heating the metal to the 'critical point' and cooling it at some rate. Tempering in involves heating the metal to low (relatively) temperature and holding it there. They all change the metal in different ways by manipulating the matrix of the iron and the alloyed elements included in it. The critical point is the point at which the alloyed elements move freely about the sea of iron. It is different depending on the alloys involved. For plain carbon steels it is ~1500 degrees F
There are several states for the crystaline structure and you can have several throughout a single piece. Martensite is the hardest. It is also the most brittle. Perlite is the softest but toughest. Austenite is the state where the alloyed elements can move freely about the iron.
Annealing is heating the metal past critical and then cooling it very slowly. Most blacksmiths will bury the heated metal in vermiculite and let it sit for a day. It will often come out still very hot. Annealing in a controlled professional environment will cool it in the furnace at Xdegress per time. The purpose of annealing is to take the metal to it's maximum softness and to remove built up stresses in the metal. Stresses come from working the metal, such as forging and machining. The metal grain has a kind flow about it and annealing allows the metal to reform this flow and make the material as a whole much stronger.
Normalizing is the same as annealing, but it is cooled faster. Instead of cooling it inside of an insulation, you just allow it to cool in the air. This makes the metal softer and removes stresses, but to a lesser degree than normalizing. It is done when the stresses built up are not severe and maximum softness is not necessary. It is much faster than annealing.
Quenching is heating the metal past critical, and then rapidly cooling the metal. This is probably the most difficult heat treating process because it creates TREMENDOUS stress in the metal because of the thermal shock. The more alloyed elements, specifically carbon, the slower it must be cooled. There are three quenching mediums: water, oil, and air (yeah air), in order of speed. Quenching something too fast will cause it to break from the thermal shock. Quenching forms martensite, which is the crystaline structure that makes steel hard. However, right after quenching, the blade is INCREDIBLE brittle. You could take a sword freshly quench and break it very easily by trying to bend it.
Once you quench something, you must temper it. Tempering reduces the hardness in exchange for toughness, the ability to resist breaking. Tempering is heating the metal to a specific temperature and holding it there allowing the metal to soak. Typically the time is for an hour, and typically at least 2 soaks are done. The higher the temperature, the tougher and softer it will make the metal. Typically, before modern metalurgical science, blacksmiths would heat the metal until it turned blue and then they would heat it no further. The temperature you temper at depends on what you want the final products properties to be. A sword would typically be tempered at a higher temperature because it needs to be able to deal with being bent versus a knife which would be tempered at a lower temperature because the change of it being bent is much lower.
There is also a technique of differential hardening. This is where you leave the edge exposed or lightly covered in clay, but cover the spine completely with a clay substance. The blade is heated and quenched. The clay on the spine prevents it from being fully hardened, thus making it very tough while the exposed edge is made hard. The idea is to get the part that needs to be hard, the cutting edges, hard and the rest to be tough. The Japanese are probably the most famous for this, but everybody did it at some point. It produces what is called a hamon and they are really quit beautiful.
The hamon is the border between the hardened part and the unhardened part.
There are also three basic material construction methods. Monosteel, san mai, and damascus. Monosteel is the most basic, where the entire blade is comprised of one alloy. The other two involve a process called forge welding. San mai is a steel sandwhich. You have a piece of hard alloy sandwhich between two pieces of tough steel. You forge weld the pieces together and make the blade. When the blade is beveled and sharpened, you expose the hard steel meat layer, which is supported by the tough steel bread layers.
Damascus steel is alternating layers of different steel alloys. They are then forge welded together, drawn out, folder over and forge welded together. This is repeated several times. This creates a very interesting pattern which can be manipulated to make new patterns. Whether or not it benefits the integrity of the blade is a matter of debate and I haven't read of any scientific studies done to make any real conclusions, that isn't to say they don't exist. However, it is NOT the stuff of legend that can cut through solid steel bars. That is Hollywood hype bullshit.
The other three parts are the hilt, the handle and the pommel. They forms a sandwich. The hilt and the pommel are what keep the handle on. The hilt is the 'hand guard' piece. It has a hole that is shaped so as to fit to the wider part of the blade. The tang goes through it. The handle, often made of wood, has a hole formed to fit VERY tightly onto the tang. This is often achieved by a process called 'burning in' in which the tang is heated and the handle, having been pre-drilled as closely as possible, is forced onto the heated metal. This will actually vaporize the wood in a manner of speaking and cause the wood to be compressed and what not against the tang. It is repeated several times until the handle fits as it should (or its ruined heh). The pommel is then put on after the handle. The blade will then have some material sticking out of the pommel which is cut to the desired length and peened down to rivet the pommel in place.
This video shows the process of making a damascus sword.
Once the parts are all put together, the final sharpening and polishing (if desired) are done.