OK, let's break it down:
1. You need money in the form of a loan to buy the house - you get this from a bank or mortgage originator/broker
2. You need a downpayment on the house - to show that you have some skin in the game. This is where VA helps.
3. You need Mortgage Insurance - because you will not have 20% or more to put as a down payment towards the house. This is where VA comes in.
A VA "green sheet" is a certificate you can use in helping you 'get into' a home. The VA sets up rules for sellers and mortgage originators (brokers, lenders) to protect military people form getting taken advantage of when purchasing a home.
The VA will dictate that closing costs be paid by the seller, that they will secure the loan and provide mortgage insurance in case of default, they will mandate certain health and safety issues on the home are taken care of, that sort of thing.
The FHA does the same sort of thing, but they tend to be quicker. The VA drags it's feet a bit since they use their own inspectors for ensuring the value of a home and the health/safety issues I mentioned. It's why people tend not to use them very much.
You need to find a realtor who has handled a VA loan before, the contracts are written differently from other styles of financing and purchasing. You need extra time for the inspections and the seller absorbs a lot of costs. You also been to find a mortgage broker who can fund a VA loan, most can't. Your first stop should be the VA to obtain the green sheet and get some advice.
I'd help you but I'm in CO :) Happy house hunting!!