I just bought a 1984 chevy diesel van. I want to run it on biodiesel, and I don't really know where to start.

If I'm not mistaken I'm pretty sure you just fill up the tank and run it like normal. The engine runs on bio-diesel, it doesn't have to be outfitted with anything specific as far as I know.

Zac's right you just have to put the bio diesel in the tank its the same as regular diesel but way cleaner

since you can not run pure 100% biodiesel in any car all year round unless you live between the 30th paralells, you will need to mix with regular diesel.

Also, make sure you have lots of money, biodiesel costs more than reqular diesel.

you can just fill the tank and run the engine on 100% biodiesel with the possibility of only minor issues cropping up. those being leaks from fuel hoses and "O" rings not rated for biodiesel. start by running biodiesel, and check for leaks from time to time. if any crop up, replace the lines and "O" rings with biodiesel rated items. if no leaks crop up, dont worry about it.