I need to learn how to make datapack

Hi guys, (sry for my bad english) i want to troll some of my friends, we are in an aternos server, playing Minecraft and sometimes triggering wars and etc, I have perms on the aternos panel, and i tried searching for a dupe datapack or something similar, so i search up, i found nothing. When i found nothing, i ask chat gpt about, he send me a datapack wich wasnt even working, i'm in 1.21.5 and i feel like the version might be the issue, So, i want to learn datapack, can someone here explain me or send a video from someone who explain how to do datapacks ? Thanks you, hope you have a great day