How do I convert my trial version of Groove?

I downloaded a trial version of Groove software and am using it - I loved it
and it answered lots of my problems in sharing files, so I responded to the
email I received from Microsoft saying that my trial was almost over and
purchased the software online - I saved the receipt of this
purchase...however - that was it! No instructions on how to convert my
software, there is activation key heading on the receipt but no key under
it...Anyone got any clues on how I activate my software that I have paid
for?? I can find no way to pose this basic sales service question on the
Microsoft site...thanks in advance to anyone who can help.