The RaspTouch IY kit is a very nice product. The parts are nicely machined, and the resulting built looks very good.
Audiophonics also provides a guide on how to put it together.
Where things do get a bit tricky is in the build: I think I was a bit unlucky as it turned out i did not receive all the screws needed for this build. Also it seems there are several iterations of the kit where some components are placed on a different location than described in the manual. The trickiest part I found was the SD card extension that had to be taken out of its casing and placed on the metal. As to make sure I would not short-circuit the piece, I first taped it up before fixing it to the metal.
Also because of these changes in the kit, not all steps and parts are self-explanatory anymore, which makes the build tricky.
But the support team is very helpful here and provides useful information and images to guide you through the steps.
Also in my case: they provided the parts I was missing, thank you guys!
Now I have this case set up with a raspberry model 3 B+ with touch and a DAC. As software I chose Moode Audio, and it sounds and functions perfectly.