I am really confused about putting the pots/knobs onto my guitar. I am replacing the pots in my strat copy and putting new knobs on it. I cant seem to get the pot to stay in place. The type of knob I am using is a top hat with a post into the side. How can I make the pots stay where they are supposed to be and have the knobs stay on properly!

The knob doesn't keep the pot on, it just lets you turn it more easily. You need to have a nut holding the pot to the pickguard. Your pots probably came with a nut or two each, they may be on the shaft yet. You need to put the pot shaft through the pickguard hole and then tighten the nut on to keep in in place. Then you put the knob on.

Is that what you mean? Or do you mean that the set screw in the tophat knob won't catch on the pot shaft? If that's the case, what kind of pot shaft is it? (What does it look like)