To start off, datapacks work off of Minecraft commands, and are only a Java Feature. You NEED to have some basic knowledge of commands to make datapacks. When I decided to make my first pack, I used this video: https://www.youtube.com/watch?v=ac6V5-KT6Rg, by Legitimoose . It gave a lot of info, and introduced me to Visual Studio Code: https://code.visualstudio.com/. I HIGHLY recommend using this tool to write code, with the Data-pack helper plus extension: https://marketplace.visualstudio.com/items?itemName=SPGoding.datapack-language-server, and the language-mcfunction extension: https://marketplace.visualstudio.com/items?itemName=arcensoth.language-mcfunction.
Datapacks work by running minecraft commands. There are functions, which can run multiple commands at once when you run the function. To summarize, just follow the video linked, and you should be good to go. If you need help, I recommend the Minecraft forums, the Minecraft wiki, the Minecraft discord, the Minecraft Commands discord, and the Minecraft Commands Subreddit, all linked below.
Datapack Coding:
Starting Video: https://www.youtube.com/watch?v=ac6V5-KT6Rg
Visual Studio Code: https://code.visualstudio.com/
Data-pack Helper Plus extension: https://marketplace.visualstudio.com/items?itemName=SPGoding.datapack-language-server
Language-mcfunction extension: https://marketplace.visualstudio.com/items?itemName=arcensoth.language-mcfunction
Media:
Minecraft Forums: https://www.minecraftforum.net/
Minecraft Wiki: https://minecraft.gamepedia.com/Minecraft_Wiki
Minecraft Discord: https://discord.com/invite/minecraft
Minecraft Commands Discord: https://discord.com/invite/9wNcfsH
Minecraft Commands Subreddit: https://www.reddit.com/r/MinecraftCommands/