Can't change my windows 10 version

Oct 10, 2018
6
0
10
So my school teacher downloaded windows 10 pro on my pc a few days ago and I brought my pc home but it says "we can't connect to your organization's activation server." What do I need for it to work? I also want to replace the windows 10 pro he downloaded to my copy of windows 10 home, but no matter what I do I can't change it. I've deleted all the files and loaded windows 10 home but whenever I go to the control pane it says windows 10 pro is the os I'm using.
 
Oct 10, 2018
6
0
10


That link didn't really explain how to backup windows 10, can you give me some information on how to backup windows 10?