Install Unity Hub and the Unity version required by VRChat
Install the VRChat SDK for avatars
Create or obtain a 3D model for the avatar
Import the model into Unity
Set up the model’s materials, textures, and shaders
Rig the model with a humanoid or compatible skeleton
Configure the avatar’s bones and humanoid mapping
Add an Animator and avatar descriptor
Set the view position, lip sync, and eye tracking if needed
Add expressions, gestures, and animations
Optimize polygon count, materials, and texture sizes
Check mesh bounds, colliders, and performance rank
Test the avatar in Unity
Build and upload the avatar through the VRChat SDK
Test the avatar in VRChat
Fix any issues and reupload as needed