Another step is finished. 
I downloaded, modified and printed that LCD case: 3DR - RepRapDiscount Full Graphic Smart Controller case by pablogil - Thingiverse
Attached is a speaker mount found on Amazon:
Additionally the tiny screws for the endstops arrived and I could install them as well.
But it looks like I have to twist the stepper connectors on the PCB as the steppers seem to move in the wrong direction. 
Lower/front left is the 0,0,0 origin is it?