Need some Computer building help?

I'm building a computer for my first time and I need some help with a compatibility question. I have a Thermaltake Element G Mid Tower Case. I'm looking at PSUs, but not not really sure how compatibility works with them. I found a pretty good deal on a Thermaltake TPX-775M Toughpower XT 775W Power Supply - ATX, 775 Watts, 80PLUS Bronze, SLI Certified, CrossFire Certified, Status LEDs, 140mm Fan PSU, but really not sure if it works with my case. It says its a Form of an ATX, but not really sure what that means. Can this work out and if not, what can?