Alright, so you’ve backed up your internal storage and SD card (if you’re using an SD card).
So basically do the reverse of what you did before - although I recommend using ADB, the Android Debug Bridge. It’s faster and more stable than MTP in my experience. It’s in most of the default repos, so yum install adb or apt install adb or what have you.
To allow your PC to connect through ADB, you have to go to Settings > About phone and then tap repeatedly on ‘Build number’ (all the way down) until the phone congratulates you on being a developer. Then go back one step, go to ‘System’, then ‘Advanced’, then ‘Developer options’ and enable ‘USB debugging’.
Then hook up the phone via USB and when it asks to trust the PC it’s being connected to, check the box and hit OK. Now you can use ADB to copy over files.
Looking at your backup, the content of the main folder presumably has two directories: internal memory and the SD card, if you’re using one.
The internal memory is mounted at /storage/emulated/0. So you’d copy over your internal memory backup with
adb push -a /home/myuser/FP3backup/<name of internal storage folder>/* /storage/emulated/0
This copies the entire contents of the internal storage backup folder over to the internal storage of the phone. The -a is so it keeps modification date metadata.
If you have an SD card and you also have to restore its data, you can do the following:
Your SD storage will have unique name, so you can run
adb shell ls /storage
and it’ll display something like
That directory with the double name in letters and numbers, that’s your SD card. So
adb push -a /home/myuser/FP3backup/<sd card folder>/* /storage/71ED-1519
Replacing 71ED-1519 with whatever your SD card is called, of course.
After doing this your data should be restored.