I have a Mk 6 Ford Fiesta Zetec S.

It's been dropped and now the wheels look too inset and I don't like it. I've looked into spacers and ideally I'd like to put 20mm spacers on the back and 12mm spacers on the front. The issue I have is that my current studs are not long enough to support this. I've found packs of studs but I don't know how to change them. Front and back. Any help would be much appreciated. Thank you.