Patching packaged software

[abitrolly]

As a user of Terminator I need to add several things to it. Unfortunately, the project doesn't get anything merged for a long time https://bugs.launchpad.net/terminator/+bug/1849375

I am in a position to learn new custom format for Fedora packaging from scratch. However, following a short straightforward tutorial that can help me get the source, patch it and send to Fedora package maintainers will be helpful.