This is a Quest Compatible Davali which is rated as Good, allowing it to be used as a Fallback avatar. This version has better seaming for it's body textures and refined blendshapes. 

- Create a new Unity Project and switch it to the Android Build Target - See here https://docs.vrchat.com/docs/setting-up-unity-for-creating-quest-content
DO NOT convert your PC Unity Project, this can break things. 
(A completely new project just reduces the chance of something erroring and you needing to hunt down what caused it)
This package is made using SDK3, use import the most recent version of it. 
    SDK3 is used becasue that is what most people are familiar with now and it allows the blink animation to work as intended.

- For the atlased texture, scale your existing ones to fit, the main are 1024x1024 and eyes are 512x512. 
For the materials you must use the shaders in VRC/Mobile, the example uses Standard Lite

The example uses an FX Animator with all the hand controlled gestures Muted, I do this so I don't have to keep the gesture config synced up between my PC and Quest versions, especially if I am using it as a fallback. I'd rather have the Quest not gesture, then make the wrong one at people. You can customize this to match your PC avatar as you wish.

You should be able to and upload the avatar to Android, you tag it as a fallback on the screen where you set it's name.