up grading from cubase 10 pro to 10.5 pro

Need a little help her, hope someone can.
I downloaded 10.5 pro update from Steinberg download assistant
At no time was I asked for money or payment which of course is not a problem.
I installed the up date, while I still have cubase 10 working fine
can somebody outline the upgrade procedure to me.
Where do I get and pay for the activation code to insert in
steinberg down load assistant so as I can update elicencer
and operate the 10.5.
Also re cubase 11 Does it run on windows 7pro
Thanks you for your help.

At this point you cannot purchase a license for C10.5 only C11. The C11 license will allow you to run C10.5 (or really any lower version) in addition to C11. You can purchase the license through the Shop link on the Steinberg site.