Problems for me, but works for others

I'm trying to upload a sketch I had found online, I keep getting errors while uploading, I'm pretty new to Arduino so I don't quite know how to fix it to get it to work. It seems others don't have any issues uploading it (unless they made changes to it without telling me they did so)

Here is the link with the code I'm trying to use :

https://create.arduino.cc/projecthub/binsun148/digital-3d-printer-filament-counter-using-ps-2-mouse-2df0da

Please post the errors here. If it works for others, there is a good chance that it also works for those that try to help you.

The project seems to use an Uno; are you using an original Uno or a clone that might need the CH340 driver? Or maybe another board.

Is anything connected to pins 0 and 1 (not according to the diagram on the project page but we can't see what you did / modified).

Are you using Create (no experience with that) or the IDE (installed on your computer)?