How do I use the f keys (volume, brightness etc.) with a pc keyboard on my MacBook Pro?

I'm using a pc keyboard cause I like the feel better than an apple keyboard, but the f1, f2 etc. keys don't work the way the apple keyboard does. Every article I've found online says to check a box that says something like use the F keys as F keys, but I don't have a check box like that in my keyboard settings.