Check out the Techiepedia section in Analogue Art. Fitting Paul's PSUs are quite straightforward so don't panic. Help is in the section with photos if I remember right, but if you have the regulators too then help on those is vague to say the least.

Ianmac of this parish fitted mine for me and even for someone as expert he is with a soldering iron it was still tricky.

I managed to PSU myself so that's easy enough.

Mike.