As far as I know you have to this:
- Install drivers and software that you have in the CD that came with PRO.
- Go to website of GM and do the register.
- After that you can do the update of the ECU, by connecting J2534 to your laptop.
In GM website will find some instructions, if you found some difficult.
If I had the chance tomorrow or in Thursday, I will do that in a Ford Fiesta of 2010.
I can put here my experience after that.