Sorry my reply's a bit delayed - as usual life got in the way.
Biggles. Thank you for your helpful instructions. I've printed them off and will work through them, leaving OneDrive until I'm happy with the new set up. I have a folder called Documents and within that is one called My Documents! Don't ask me why, it's just the way I set it up many years ago. My Documents has more personal stuff in it, whereas Documents seems to be folders to do with the the laptop, although sometimes, and I don't know why, when I save things they go into Documents as well as the folder where I want them to be. I go through them every now and again and delete any duplicates. I guess the Free File Sync you mention would save me doing that.
If it's not a silly question, how do you put Folder named "Documents" into your portable hard drives?
My laptop was backing up weekly to the external hard drive. I've changed it to daily at the moment because I'm doing quite a bit of updating to my family tree and I don't want to lose any of the work. However, I've just looked at the backup from Wednesday (I forgot to plug in the hard drive yesterday!) and nothing opens. I'll see if I can attach a photo of it. I'm not sure what's going on.