Moving files around is a key skill in Windows (what I call "data manipulation") and if you can learn this it helps a lot in using a computer.
Data manipulation include creating folders, moving files and so on.
You can copy and move files with "copy and paste" or "cut and paste" and you can also use "drag and drop".
If you don't know how to do this then it sounds to me like you have never taken any backups.
If you have never taken any backups then this is VERY risky as all sorts of things can go wrong with your computer and some of them can result in your losing ALL the files on your hard disk.
So those Excel files, or your family history, could all disappear in a few seconds, never to be seen again.
Please get in to the habit of taking REGULAR backups, either daily, weekly, or monthly, depending how important your data is.
Also don't backup to just one place. Put a copy of your files on your portable drive, but also put a copy on to CD or DVD, put other copies up in the "cloud".
There are many "free" cloud solutions such as OneDrive (from Microsoft) or Google Drive or Dropbox.
Basically you register for one or other of these (or both) then just "drag" the files you want to save into their folders. The files are then saved in those folders up on the internet.
Then if you install OneDrive or Google Drive or Dropbox onto another PC then the files are automatically copied across to the new PC.
In fact if you buy a new PC with Windows 10 on it it will already have OneDrive on it. So if you put OneDrive on your current PC, copy all your files on to the OneDrive folder, then when you start to use the new PC the files will be copied to it automaticaly.