Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I want to second what 007 said but with different words:
Can a novice do this: Yes
Can a novice make a mistake and render his computer inoperable: Yes
Editing the Registry is not without risks and most articles strongly advise making a Registry backup just in case. The problem with this is that if your computer will not boot up at all (and yes this can happen although not likely) it will be a real challenge to get to the saved backup.
Do you have a friend who is familiar with computers? The best way to learn this is to have someone walk you through it. Alternatively you can post questions here; you will get good advice but it make take time to walk you through it. I would also second the comment about googling "Editing the Registry in Windows 10" and trying to get a feel for what is involved. You will have to open RegEdit and then search for "TargetedMessagingService" [no spaces] and then follow the steps outlined in this thread to edit the Header/TimeToNextcall [no spaces] to the year 2025 or some other date. That date is when the banner will appear again.