Installations Issues for Lightroom (Please help)

I purchased Lightroom from the Office Works website.  I have my serial number.  When the link to install was clicked a pop up appeared which was to create an icloud account.  I clicked no and not to ask me again.  Unfortunately it seems like it was an important part of the installation.

I then went through the process of downloading a trial thinking it will ask to purchase or enter in a serial number at the end of the trial.  It only asks me to purchase it which I don't want to do.  Does anyone have any ideas to help me?