Download and install a mod loader such as Forge, Fabric, or Quilt
Download the modpack files from a trusted source
Open your Minecraft launcher
Create or select the Minecraft installation profile for the mod loader
Set the correct Minecraft version required by the modpack
Open the modpack folder
Place the modpack files into the correct Minecraft directory or modpack launcher folder
If needed, install the modpack through a launcher such as CurseForge, Prism Launcher, or Modrinth App
Launch the game using the mod loader profile or modpack instance
Check for missing dependencies or version mismatches if the game does not start
Allocate enough RAM in the launcher settings if the modpack is large