how does construction with a va loan work

I’m very strongly debating on living in a camper now on a piece of property i’m about to buy. I won’t be able to use the va loan for that obviously. however I am debating on living in my camper for about 2 years give or take a year or so and i’d love to build a house using the va loan. how is it possible and is it possible at all. also how long do you have if you can get a building va loan how long do you have to build it and do you have to go through a contractor. Thanks everybody.