Today I soldered in the switches and led into the pcb.
For this part of the project It is important to line up the keys when you are soldering them in, to keep them straight. If you fail to do this it can end up with your keys being angled.
Properly insert the key pins into the pcb, and also ensure the leds are properly placed.
From there you can just solder them in, this will allow you to use the keypad with the default settings which is media control.