Removing stock side skirts?
 

Just wondering if I have to remove the stock side skirts to put on the new ones and if I do how do I get those screws or whatever they are out?

lol...... ofcourse you have to take off the stock sideskirts off first.

There are screws holding the front and rear of the skirt. Then are are about 10 plastic screws on the bottom. Take them off and you'll have to slide the whole skirt forward to un-secure it. Not hard at all.....

And when you want to put the new ones on, its 10x easier to remove the origial clips from the car (twist and pull out), and put them into the new skirts - then just pop them into place.

how do I take out the plastic screws without breaking them?

just carefully

your gonna break some, they always break those damn annoying snaps

I really hate those plastic screw things on the bottom. I have like 10 new ones as back up parts because I know I'll strip the old ones out.
I wish they were just regular stainless screws

How do I attach the clips onto the new skirts?

You got aftermarket ones, didnt you? Your best bet, if you can do it, is to make similar slot things (like stock) and attach with fiberglass or epoxy (Im guessing your replacing stock with fiberglass).
A body shop can do it too...for a way-too-much-than-its-worth price