So I'm trying to make an assembly of a mouse with multiple buttons and a scroll wheel. Then I realized that I can't mate the parts (side buttons) to the mouse because the mouse I made is technically just a shell; and solidworks won't let me mate the parts to the shell's cutouts.
Can anyone help me out by telling me how to fill the mouse shell, so that the parts could be mated to an extrude of the mouse button cut-out instead of the surface cut-out of the buttons? Thanks in advance
*Attached below is the main mouse shell and the intended buttons