MIdi sequencer (adapting code for own purposes)

Hello everyone!

I saw a tutorial by adafruit on how to buid a wireless midi drum sequencer that works with BLE (bluetooth low energy) and capacitive touch pads by using a adafruit feather . (https://learn.adafruit.com/bluetooth-le-midi-controller/overview)

I would like to build the same machine only using midi over USB as shown in this tutorial (as shown here: https://www.youtube.com/watch?v=s-gcZ61Dj5g&t=620s) with the same capacitive touch capabilities and sequencer as present in the other version by flipping the arduino.

I´m still a beginner with arduino but I understand that what I would need to do is delete all the code pretaining to the feather (including commands and libraries) then insert the midi library and substitute the midi Ble commands for regular midi commands.

The problem: I have no clue how the code is structured in order to construct the sequencer and what lines are required for the bluetooth or for the general running of the program. I´ve done research into how to program a feather to use BLE in case that would help me discern the purpouse of each bit of code and though it is commented I still cant find a clear meaning for them.

Could any one give me some guidance or refer me to any helpful links. Any tips, thoughts or help would be very much appreciated :)

The code I´m working off of is in the example sketch called nble_neopixel_mpr121 inside the Fifteen step library.

Thank you all in advanced