I got bahamut, and I'm in the bottom of the reserch center. I've read the instruction thing explainin the steam and the blocks and the energy and stuff and the door is open. But I can't get in, everytime i try to go down the stairs Squall always gose back. I read a walkthrough and it says that Zell is component, Do I have to have zell in my party? I havent really spent time leveling him up...

Well leveling up isn't really a must in FF8 so don't worry much about it, just as long as your junction and your hp is high enough you can be fine and complete the game with ease.
Anyway, Zell should be in your party so you can activate the machine w/o using any steampoints or whatever and that way you don't have to go up again.

<font color=red face="comic sans ms">Using Zell to open the door at the bottom isn't always the best idea. It gives you battles with strong Lv100 enemies every few steps that you can't escape from and can't be avoided with Enc-None.

To get down, I think you either need to use 2 or 4 points on the first floor (try 2 to start with, if it doesn't work reset and use 4). Then 1-2 to get to the next floor (again, try 1 first, then 2). In the next floor there should be a room with reserve steam units, so you can go in there and you get 7 more units. Then just keep using as few as possible to get down, and you should have 10 when you get to the bottom, which is just enough. :)