Thanks for the responses! So it all worked out. I'm just so glad that everything went ok. I built this pc from scratch, my first time.
So yeah I just took one of the cables from the PSU, it has 3 molex connectors on it, plugged one into each of the fans that comes with the Antec 300. Left them on low, started up and they started spinning, and the little controller that hangs off will change the fan's speed.
My build is pretty moderate, i3-2100, 8GB Ram, eVGA Geforce GTS450, seagate 1tb hdd, dvd-rw, antec 550W truepower. So I think, and you can tell me if I'm wrong, cooling isn't going to be a major issue. I just used the stock intel CPU heatsink and then the Antec 300 has one rear and one top case fan. Would you add one on the front where it has space for two? Or is that unnecessary. I think that it says in the motherboard manual that there is a program on the driver disc that allows you to see temperature readings for your computer.
What a relief, I just installed Windows tonight, I was worried about the motherboard, It's a Gigabyte P67A-UD3-B3, and I was reading the reviews on Newegg, and half of them were saying "It's unusable!! Gigabyte should stop selling this it's killing their reputation, it just reboots every 10 seconds over and over in a loop!" and then the others said it works fine.
Biggest pain was getting the video card to go in, everything else - just took my time and read the manual and it was ok. Had to ask a few questions along the way, ie. the motherboard has 7 screw holes but the case only has a spot for 6 of those standoffs to go in and I wasn't sure if that was a problem, apparantly it isn't.
Fun experience though overall, I'm glad I built it vs. just buying one. Though I realize it might just be luck that I got no defective components or screwed anything up in which case I might have said it was a nightmare!