To activate your software you will need to know your Serial Number and PIN.
These will have been supplied when you purchased the software, either by email or with your installation CD.
When you have these to hand you need to run the Reporter Professional Plus Licence Activation utility.
This was probably started when you initially completed installing the software, but if you need to run it again you can find it under the Start Menu. Just go to "All Programs" and look for the "State Of The Art" folder.
Full instructions on how to activate the software are displayed in the activation utility.