You are putting the very large cart before the horse so to speak .

First you need to learn basic game design ( Or hire some one that knows )

Next you need to learn how to program ( Or hire people that knows how )

Than you need to learn networking ( Or hire someone that knows )

Instead of attempting to make a 3D shooter, aim to make something a lot more simple - a simple network chat program that uses basic emoticons .

After that, go for something a little more complex - a 2D multi player sandbox game.

From there you could move on to a 3D multi player voxel world.

From this point, you should have learned enough to attempt a basic multi player 3D shooting game.

If you have mediocre or poor long term planning and management skills, attempting to put together a "team" will result in internal conflict, people dropping out, and an all around bad time. Please READ THIS before going any further in attempting to recruit.

I only know the design aspects of making a game, I'm horrid at programming and my 3D rendering skill leave a lot to be desired.

Sorry to say it, but unless you're able to pay people you'll find it very difficult to recruit skilled team members if you're a designer (especially if you're an unproven one who can't show prior work!) who won't be contributing technical skills to the project. I recommend a read through the old topic "what programmers want from a designer", where you'll find a number of lengthy and detailed responses detailing what your potential team members might expect of you in such a situation.

But do you have to rent a server, or If put in steam is space on a server provided?

Unless it's designed to run in a web-browser, players need to download your game client from somewhere; this involves a web-host (server) where you would host your website and the download. If your game is on Steam you don't have to offer a separate download, and web-hosting would not be needed unless you also want to have your own website -- most games do still have a website for marketing purposes.

However, as you want to create a multi-player game you may or may not need a server for players to connect to during the game (or possibly just for match-making) as well! See the next part of my response for a little more on this...

I went a head and got a team together to bring this idea to life, how would you implement the online part of the game?

There are a number of different possible answers to this depending on the specific needs of your game and how it's being made, and as you're a non-programmer I'm not sure how much technical detail would benefit you, so my suggestion would be that you would sort out the specifics of your implementation with a programmer who understands the intended design of your game in more detail. It may well involve renting a server, so be prepared for the fact that this may be a cost you have to pay for. If you still want to try to sort out more of this yourself beforehand you might try starting with a read through the Multiplayer and Network Programming Forum FAQ and then come back with any specific questions you still have.

Hope that helps! :)