Be sure to search the community before making posts like this if you can. If you did, then it might be an issue because there isn’t an actual step by step guide hosted on this website, per-se. We’re working on that. The information is mostly here:
You can also browse the home made section:
Several of these include helpful information on how to make your own.
This may also be useful as you’re using a Pro Micro.
If you want full speaker and LED functionality, you’ll have to go with the “Alternate Wiring” diagram in the Production Arduboy Schematic thread that @bateske sent and then you’ll have to use this library instead of the standard Arduboy2.