(next time, start here https://www.youtube.com/watch?v=WpXE3v3m8zw&t=101s not sure if that works but looks like maybe) or unrelated activities here https://www.youtube.com/watch?v=TiwmAPjXFcE&t=160s .
Note that if your Arduino is not detected it is often that the cable isn't a data cable but just a charge cable. Note that Arduino Pro Micro detects as Leonardo and that is fine. There's no difference except the physical size of the board.
Not all Arduinos have midi capability. Only those with the ATmega32U4 (which has HID capability ie it can be recognized as a keyboard or mouse. Leonardo and Pro Micro. But the ATmega32U4 still doesn't have midi out of the box but you can add a library (the 'midi USB library').
To import the library, in the Arduino IDO do (menu) Sketch > Library > manage libraries > (type) midi USB > ‘midi USB by Gary Grewal’ > install it.
(Note that you can actually use Unos and Megas etc but that's a method called hairless to use them as midi controllers.)
If you plug this into your laptop and have Ableton open, it should just automatically detect an Arduino Mini is plugged.
Tutorial on YouTube by Nerd Musician https://www.youtube.com/watch?v=32myesnWLuY and he has other videos including a 1.5hour full tutorial.
Plug in Arduino Pro Micro and select ‘arduino micro’ as board and etc.
If you get ‘Failed uploading: no upload port provided’ error upon upload attempt, if your ‘Tools > Port’ menu item is greyed out,
Hello Drum library. With the Arduino IDE program opened, go to manage libraries and it will be there in the search (downloadable). I also downloaded it locally and put it in the Software Folder "avrdude: stk500_getsync(): not in sync: resp=0x00," aka Some Dude Named Avr Won't Let Me Upload My Program ... ... This error, retry evertying, and then do Tools > Processor and try the at least 2 options 328 and 328 Old Bootloader. This worked for me.
"These library allows any microcontroller with native USB capabilities (atmega32u4 based boards or ARM boards) to appear as a MIDI peripheral over USB to a connected computer.)"
The biggest issue is that the Nano does not have built-in (silicon based) USB Client support.
As the error states; You need to use an Aruino Pro Micro or Leonardo (for instance, there are many others) that are based off of the ATmega32u4 processor instead of the ATmega328 which is what is used on the Nano.