Help with servers.

Hello, my name is Cody, I'm in an IT class and we are doing a project where we need to design a network build for a fake gaming company. My friend and I have the job of finding a suitable mail server and a local file print server, and I would like to have some recommendations from some of you people out there who know a little bit more about this than I do. I need to know what kind of parts to buy if I were to design a build off of Newegg and what quality the part should be, for example I may need ram, but how much, or I may need 2 CPUs but how many cores and what clock rate. I also need to know would it just be better to buy a server outright from dell for instance. also what kind of software should I be getting for these servers?

the fake environment these servers would go in is an office in Boston housing 75 employees. I'm not sure but I think these employees are going to be working in administration, or something like standard office work.

thanks for your answers and if you need more info just tell me.