How do I save my data to a USB stick and transfer it back later?

There's a problem with our notebook. The technician said I should perform system recovery, previously transfer the data to a USB stick and later save back to the notebook. How do I do that?

You have to insert the stick into the drive and then press ALT + F4 and directly enter

Copy "C:" in Explorer then right click on the USB stick and select insert

And if I want to store back again?

You can either copy only parts back, you select the desired folder from z.b. "Document X" with a right-click copy that and then paste it in the desired location with a right-click ("paste" must still be selected) in the folder.