>>1864581add plus nuts to van metal.
bolt 2x2 to wall using plus nuts on both sides.
lay boards across top of 2x2's with some space inbetween. glue and screw
once you start not being scared to build shit you learn really fast. Cordless drill, impact driver, circular saw, $40 Kreg pockethole jig, contour tool are must haves. Once you get to the point where you are cutting holes in the middle of wood to add switches and covering contoured parts of the van you'll need to buy a jigsaw or oscillating tool.