To activate your license you can use the IBM Installlation Manager as described here
You will need an activation kit.
First you need to know if you ordered your product through the software channel (Passport Advantage) or the hardware channel (eConfig/AAS)
If you ordered through the software channel (Passport Advantage) you can get a copy of your activation kit from the Rational License Key Center.
If you ordered through the hardware channel then you can follow the instructions in the blog
Hope this helps,