@Tylah What kind of power switch? If you're referring to the standard PSU power switch on the back, that's pretty standard and is used to provide or cut off power to the PSU from the cable you have plugged in. It cannot be used to turn the PSU on.
Don't worry, it should be pretty simple to get your PSU powered on. When you install a PSU, there is a main cable that gets plugged into the motherboard. The power button on your PC gets connected to the motherboard. Whenever you press the button, the connection is closed and it "jumps" the PSU. The idea behind the "paper clip trick" is to mimic that connection.
From Google: Plug the AC power cord into the power supply. Have the AC coming directly from wall outlet without any filters or UPS. 5. Short between the green and black wires on the 24-pin connector (as show below), with a paper clip or piece of wire.
Here is a nice tutorial on the procedure: http://aphnetworks.com/tutorials/psu_paperclip_trick
I would say to be careful while doing this, especially if you don't have experience with power supplies. (I don't want you to get shocked.)