if i want to make a game, a 3d game, and i want to use direct3dim, what else do i have to do with direct3dim? do i only have to initialize d3dim, make primitives, and handle input? do i have to worry about the order of drawing objects and bsp trees, or if objects are behind the camera do i have to tell the program not to draw it or does d3dim do it? what stuff do i hav eto do to make the games and what don't i have to do because im using d3dim?

With the exception of backfaces (if you have the option for culling turned on) D3DIM will attempt to draw every polygon you give it. So, it is certainly in your best interest to reduce that number if you can. Oh, D3DIM will also provide you with z-buffering.
Of course, alot of what you are talking about depends on the type of game you are building. If you build a 2 player 3d fighting game, backface culling with a z-buffer may be all you need. Usually. Good luck.