So I found this touchscreen display on the DFRobot website which is originally designed for the Raspberry Pi but finds its application in many places.
The display has a full-size HDMI connector for display and a micro USB connector for touch.
Let's start with the fun now. I recommend you to watch the explanation video I've made.
So here we need the touchscreen display from DFRobot: LINK
The display comes with standoffs, screws and a HDMI connector as well to connect to a Raspberry Pi with the display easily.
I would also recommend getting your PCB manufactured. You can order your PCBs from PCBWAY as they offer 10 PCBs for just $5. Check out their online Gerber viewer function. With reward points, you can get free stuff from their gift shop.
Test the display with a Raspberry Pi
So there are 4 mounting holes for the Raspberry Pi on the back of the display.
Just place the Pi on those holes using screws and standoffs provided with the display.
Once you've securely fixed the Pi to the Display, now using the HDMI connector provided with the display connect the HDMI port of the display to the Raspberry Pi.
This should be enough for using just the display. To use the touch you need to connect a USB cable from the Pi to the micro USB port on the Display.