Now you should be done with building the cabinet. From this point you will be installing the retro pie OS onto the raspberry pi 2. I recommend downloading the retro pie image from the official retro pie site.
First you will want to reformat you sd card using http://www.softpedia.com/get/CD-DVD-Tools/Data-CD-DVD-Burning/Win32-Disk-Imager.shtml
Then you will need to put the image file onto your micro SD card.
At this point you should get your roms from whatever website you will be using. And put the roms into the directory folder in the SD card.
After this you will need to start up the Raspberry Pi 2. Assuming that ends up working you will then have the emulator working from there I recommend checking that all the buttons are working and if not recheck the control board to see if anything became loose.
- Make sure you have completed the cabinet and have all the components in.
- Reformat your sd card
- Add the image file and the roms.