Install Minecraft Java Edition
Open the Minecraft Launcher
Select the version you want to mod
Install a mod loader like Forge or Fabric
Run Minecraft once with the mod loader installed
Download mods that match your Minecraft version and mod loader
Open the Minecraft folder
Open the `mods` folder
If there is no `mods` folder, create one
Move the mod `.jar` files into the `mods` folder
Launch Minecraft using the Forge or Fabric profile
Check that the mods appear and work in-game
Keep backups of your worlds before adding mods
Remove any mod that causes crashes or conflicts