I ripped off triangular peices of tape off my tape roll and you put them on your gun and spray paint over it. You can add more colors by after each coat adding more tape. Just make sure that its not over other tape...
Mine was a little bit more complicated. I Originally was going to cut out a section and permanently attach the mag but I changed my mind halfway through lol.
I basically got an m14 mag, cut it the size i'd like. Outline it on the gun. Dripp two holes for wooden dowels. et a piece of wood that'd fit in the m14 mag. Attach and glue to the the dowels. Attach and glue dowels into the holes in the stock tightly.
Then I drilled two holes in the bottom of the M4 mag and screwed the magazine into the piece of wood sticking out from the stock.