Modify arduino leonardo code

Hello, I have a question, I want to modify an open code that was published, the code is called: Daemonbite Arcade Encoder, is it possible to edit it? The code is for Arduino Leonardo Pro Micro Atmega32u4 I am new to the world of arduino and I need help

Yes, but that is not your question.

I have moved your topic to the appropriate English language category of the forum @xseptyx.

In the future, please use the forum category appropriate to the language you are posting in. The International categories should be used if you are posting in the language to which they are dedicated, while the non-"international" categories should be used if you are posting in English. This is an important part of responsible forum usage, as explained in the "How to get the best out of this forum" guide. The guide contains a lot of other useful information. Please read it.

Thanks in advance for your cooperation.

Yes it is possible to modify it
Depending on what exactly you want to modify you have to learn different levels of programming.

not true. You joined the arduino-forum 2 years ago and made a similar project.
It might be that you only took an existing sketch and flashed it into a microcontroller.

This forum works this way:

You yourself make a first attempt to modify the code.
This own attempt might start with the question "which of the files provided here "

Do I have to modify?

As long as you ask specific questions on how to proceed or what to RE-modify to make your modification work,

you will get answers.
It is very unlikely that somebody will write a full functional code for you.

So next step is to provide all the detail-information to make other users understand what you want to do

I'm pretty sure that you agree and will follow the way how to solve your problem mimimum 200 minutes faster.
This requires to invest 20 minutes of your precious time to read how to speedup solving your problems.

Here is a tutorial with informations how to speed up solving your problem.
You should really read it.

best regards Stefan