Install rigmod on Fabric
Install guide for the DonutSMP rig mod on Fabric: loader version, mods folder path, first launch, keybinds and the three failures that cause most crashes.
Ninety seconds, four steps, three ways it goes wrong.
Loader
Use Fabric Loader 0.15+ on 1.20.x and 0.16+ on 1.21.x. Forge will not load the jar. A modded launcher profile that bundles Forge is the most common reason the mod "does nothing."
The jar
Drop donutsmp-rigmod-3.4.1.jar into %appdata%\.minecraft\mods on Windows, or ~/Library/Application Support/minecraft/mods on macOS. Verify the SHA-256 first.
First launch
Join any world and press R. If the panel opens, the hooks loaded. If nothing happens, check that the profile in the launcher is the Fabric one and not a vanilla profile.
Keybinds
R opens the panel, Shift+R hides the overlay. Both are rebindable in Options → Controls → Key Binds under the Rig category.
Common failures
Java below 17 crashes at launch. Two copies of the jar in the mods folder cause a mixin conflict. A resource pack that overrides the HUD font can clip the panel text — remove it or switch the panel font in config.