the extrude it so it will become a 3D object. Select all and make its gray color so we can see well.

now give the side of the case some detail

Now for the bolt if have followed this tutorial carefully it will be easy to make a bolt like the one the picture:

Note: I haven’t made the screw of the bolt because it will not be seen anywhere but if you want to make it take your time ;).

After you make the bolt just place copies of it where it is needed.

Add some detail to the other side of the case too:

Now let’s move to the back. Start with extruding the back polygon