I am wiring a strobe light and then an over head light that has it's own on off switch. Can I put them both on one switch? If so how do I wire it? This is a 12 volt system on a camper.

You can wire both directly to the same switch. The only provision you need to be sure of is that it can handle the load and be sure to install a fuse in the circuit. Positive power to the switch and then from the switch positive power to the lights. Negative power can be body ground.