Just changed my radiator on my car as it had a nasty hole. Now is there a proper way of filling the system up?? like have i gotta "prime" the system? if so how??

Im gonna put in some anti freeze aswel, is there a particular ratio? like 20% anitifreeze 80% water?? And the water system is empty aswel cus as ive said ive just changed my radiator does that make a difference?

Id post this in the tech section but its dead in and id get a much faster answear in here