Part 1: Don't use raft or support for the frame.
Part 2: For the plate you should use support.
Part 3: The board holders do not fit. I'll fix it with a drop of super glue. (UNFINISHED)
Part 4: Feet so that the frame stands. These are later removed when the housing for the electrical components follows.
To connect the parts 1 and 2 you need: 4x M3 screws, washers and nuts.
The screw length should be between 8mm and 16mm.