I've started offering a variety of tutorials on my Discord server on various topics related to Opensim, mostly on PBR for now, but I will expand them as opportunity arises. Here are the current offerings:
General Firestorm Settings for PBR
Acquiring and Creating PBR Materials
Preparing, Uploading, and Applying PBR
PBR Reflection Probes
GLTF/GLB File Uploads
Coming Soon: Understanding PBR Texture Types
You can find my tutorials channel on my Discord server here:
https://discord.gg/SMBaqan3Ny