Beginner needs help on angled base plane

[bejant]

My goal is to draw the complete top, but not the hull.

first of all, bejant, I could not have a look at your example drawing yet.

ok, so I have to make a body for each part to be cut.

If you're only going to laser cut flat 2D pieces, and you trust that the plans you're working from are correct, you don't need to use Part Design or Bodies (you could probably only use Sketches for the outline of each piece to be cut). If you want to model each piece and make sure everything fits together before you do any more cutting, you would want to make a 3D model of the remainder of the ship, and for that you'd probably use Part Design and Bodies.