I have studied the following procedures, as always, to be realized by all.
Bequired, drill, jigsaw, hot glue, vinyl glue, file, rasp, sandpaper, plus the usual tools.
A piece of plywood from 300x300x15 mm.
A piece of plywood from 300x300x10 mm.
A piece of plywood or plastic from 3 mm thick.
Two pieces of wood like chopsticks.
Various coating and finishes.
In my case the drawing was done for the Galaxy S, so if you have a different phone, you have to adapt the design to fit.
In the attachment drawings in dwg and pdf.