After buying some wood supports, I've decided to make a simple frame. That will be a wall in the future. To make things simple I've cut one wooden piece in half so I would assemble two full size supports with 2 half sized ones. It's better to drill a hole before putting screws into the wood to avoid cracks. Pro tip: Get a cordless tool. Pro tip 2 : Get a drill fastener with magnets, so one can swap drill tool to screwdriver in a second.
To make a rectangular frame, it is advised to measure and compare the diagonal lengths - corner to corner. Without this step, the final shape won't be garanted.
There are few kinds of wood. Obviously the cheapest is the best. But one thing will literally be bummer: If the wood had "eye" or branches before cutting. Indeed "eye" will have two effects: