Hello there,
this is what xrandr -q answers:
janik@linux-5jxv:~> xrandr -q
Screen 0: minimum 320 x 175, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
1920x1080 50.0*
800x600 51.0 77.0 78.0 79.0 80.0 81.0 82.0 83.0 84.0 85.0
640x480 52.0 92.0 93.0 94.0 95.0 96.0 97.0
1680x1050 53.0
1440x900 54.0
1400x1050 55.0 56.0
1280x1024 57.0 58.0 59.0
1280x960 60.0 61.0
1280x800 62.0
1152x864 63.0
1024x768 64.0 65.0 66.0 67.0 68.0 69.0
960x720 70.0 71.0
928x696 72.0 73.0
896x672 74.0 75.0
832x624 76.0
720x400 86.0
700x525 87.0 88.0
640x512 89.0 90.0 91.0
640x400 98.0
640x350 99.0
576x432 100.0
512x384 101.0 102.0 103.0 104.0 105.0
416x312 106.0
400x300 107.0 108.0 109.0 110.0 111.0
360x200 112.0
320x240 113.0 114.0 115.0 116.0
320x200 117.0
320x175 118.0
Both screens are connected now, but I only connected the second one after I already entered my OS. Is there a problem with recognition?
And to be honest, you could have shown me a map of the Zurich-Underground and I would’ve known more about what I need to do ^^ (No offense, as I said, newbie to Linux 
)
I’ll do the installation of the driver you recommended and post what xrandr says afterwards.
Thanks so far!
//edit: I already installed that driver, sorry, I answered before I took a closer look at the link.