This guide uses as examples the Advanced Genie Editor codes from Wololo Kingdoms DE. Most of those codes are the same for Comunity Patch v1.6 except for things speciffic for Definitive Edition civilizations that have been deleted for that mod.
Back in march 2020 I had no idea how to create mods. I have a basic understanding of programming and assumed that there was a big file somewhere storing unit stats, technologies and so on. With that knowledge, I assumed that adding balance changes like +1 armor for certain units or faster research time for a technology had to be easy.
During that time, Europe was going through the worst of the covid pandemic and several countries, mine included, where on lockdown. Despite not being able to go outside, my girlfriend and I like Age of Empires a lot so we had things to do together.