In the toolbar at the top left of the pprune page, click on UserCP
At the bottom of the list click on miscellaneous options and select the full wysiwyg option.
Now that you can see the Quote option, let me know if you need any help on using it.
FAQ
Reading & Posting Messages
This section ends with a link to bb codes. That makes interesting reading. If you still can't get the quote option, just type the codes and it works.
Duncs,
airpolice missed a couple of steps. User CP - settings and options - edit options - misc...
well spotted.