Rule #1; visit your nearest VA office and get you questions answered; they're there to help you.
Rule #2; get your Certificate of Eligibility
Rule #3; Check out the Navy Federal Credit Union; they serve all four services.
I just hitched a Client up with them, and he is really happy.
Not many rules for buying a single family home. Lots of rules for buying condos, townhomes, etc. basically if the association is a condo association the complex has to be approved by FHA/VA and you can find the approved properties on the FHA.gov website.
I know the rules, many Realtors and lenders do too. You should ask them and specify which property since it can make a difference. The main rule is that you must have VA eligibility from being in the military.