How to replace A arm internal bearing??

Hi all I'm seeking some info about how you remove and replace the internal bearing of the rear A arm for my Stohr. Upon stripping the car we found ours had seized and all efforts to loosen it have failed. We have purchased a new bearing but I have no idea how you remove the old one and put a new one in? any secrets.

and please use layman's terms I'm only a driver not a mechanic :confused::rolleyes:

Cheers

Attached Images

a arm close.jpg (83.0 KB)