permalinks change keyword rich post title

Hi,

I have wordpress version 3.1. very new to it. I want to change the permalinks so the url shows up with the category. It seems very easy but mine does not appear to be working.

In the permalinks section it has section called custom:

what exactly do i put in the text box? Do I need the whole code? i.e. https://…etc?

when I did it last time google failed to pick up my previous posts. I dont want to loose these. so at the moment i have put it back to the default but I need it to be keyword rich for the future.

thanks for your help

Nick