Welcome to the forums and to building computers! I hope you get as much fun out of it as I do.
not sure what desktop case to use.
Great thing about building is you get to decide. Right now, if you stick with the mobo you mentioned, just make sure the case will accommodate an ATX motherboard (that's the kind you selected). Most cases will, but some smaller cases will not (they're geared for mATX)
Will all these parts work together?
So far so good, but you need to figure out what you want to do with this computer. Is it for games? Or school? Work? Also, what are you willing to spend? That's going to help figure out what parts to get. These are questions you really need to know before you start assembling components.
will any disk tray work with it?
Not exactly sure what you mean here, but I'm guessing you mean DVD or Blu-ray...? If it is, then yes. Any special features may require drivers, but that should come with it or you can download it.
is the fan enough? do I need a heat sink and how do I get one to fit or does it come with?
I think you're getting a little confused with what you've selected. You listed a heatsink (probably has the "fan" you're talking about). It will list which CPU sockets it is compatible with (the Gigabyte is an 1155 and the EVO should be compatible).
Before you continue, make sure you have a basic understanding of computer parts and what's needed. Looking at your post again, I'm not sure you know exactly what's required or what to look for. You may want to talk with someone or read several of the "How to" build articles.
Hope this helps.