In case you run into major problems with Windows it’s worth creating a recovery USB drive that at least lets you get up and running again.
You will need at least a 4GB USB stick which is empty.
Here is a guide on how to create the recovery media:
You now have a recovery USB drive that can fix your computer should something go wrong with Windows 10.
Please note, this process does not backup any data files in any way! It is only a way to reinstall Windows 10.