ADB Access in TWRP recovery mode - samsung A3, Linux

I can access my Samsung A3 (a3xelte) in "normal" mode in Linux using adb. Today I installed the TWRP 3.2.3-0 recovery mode and entered it. According to [this DroidWiki article](https://www.droidwiki.org/wiki/TeamWin_Recovery_Project#ADB_im_Recovery)(the article is in German), I should be able to use adb commands in this mode as well. However, "adb devices" shows me nothing. Any ideas or is the information wrong for this phone? Reason I am asking: After resetting the phone to factory settings, some valuable Memo-Notes seem to be deleted. I would like to copy an image of the partition to my computer (as described in [this answer](https://stackoverflow.com/a/49287932/2135504) from StackOverflow), and then use testdisk to potentially still find the relevant deleted file. The phone is not rooted which seems to make things a lot more complicated...