Step 1: Remove circlip with the dust boot

Step 2: Hammer the joint out with a metal pipe

Step 3: Place the new ball joint in the upper arm and hammer it in. Make sure to follow the marks. The marks are stamped in the metal (illustrated in red)

Step 4: Reinstall circlip and dustboot

This UCA has pretty much lived its life. But for the tutorial it's alright. I hope this tutorial helps someone.