First, make a copy of all your files from ~/ , your home directory. How to properly copy files from hard drive to USB flash drive in tty4 terminal? spells out the steps, so let's discuss it. BTW, you can run this from any tty, not just tty4.
The example linked above assumes you will copy your data to a flash drive, but that's not the only way. You can use an externally attached USB hard drive or solid state drive, or an internally attached drive of either of those types. The important thing is to avoid overwriting your source drive, which is probably /dev/sda , but you will find it when you run lsblk in step 2.
Step 2 may have found where your destination drive was mounted; the example there was /media/me/4C45-110F. Great; we'll use that in a little bit.
If your PC did not find your destination drive automounted when you ran lsblk, then we will mount it . It will appear in Step 2's lsblk, just not with a mount point, if not mounted. So, we give it a mount point, by Step 3's command
udisksctl mount -b /dev/sdXY
where X is the letter assigned to the destination drive, and Y is the first partition on that drive. X will probably be b but you will need to carefully confirm that by looking at its size and matching it to the known size of the destination drive. Y will probably be 1, but could be 2, based on what lsblk showed you.
udisksctl mount will return the name of the drive partition you will copy your files to. Write that down, and copy it carefully. In the example it was /media/xieerqi/A669-34EF but xieerqi will be replaced by your username, and A669-34EF will be randomly different. In the next line, substitute what you found
rsync -av ~/ /media/xieerqi/A669-34EF/~
That's a little different than the example, but will catch everything in or underneath your home directory or ~/ .
Then, when complete, Step 5 will safely unmount the destination drive; remember it mat be named different, depending on what we found with lsblk in Step 2.
Once you have copied those files, please take the destination drive to another Linux computer and look at its files.
Did you get everything you expected? Great!
Did you get more than you expected? You can carefully delete what you don't want to keep (or move to a different folder, which is safer).
If you see files missing, check back here.
Ctrl+Alt+F7, why do you addFn? – schrodingerscatcuriosity Aug 15 '19 at 17:29