What is the procedure for filling a new radiator in a 2003 seville
 

So the radiator in my 2003 Seville SLS sprung a leak so I bought a new one. I removed the old one yesterday, and installed the new one. I’m about to fill it up but I just wanted to learn the correct way to fill it. (I have the GM dex cool coolant). I also wanted to know how you guys purge the air out the system. I read somewhere online that you need to add some type of pellets to the system? Is that necessary? Any help will be greatly appreciated. This is my first Cadillac, and only my second time putting a new radiator in a car, so any help would be greatly appreciated.