You mean this: https://www.hoperf.com/modules/lora/RFM95.html ?
Did you look at the 'Design documents and resources' on that page?
That's a Hope RF product - nothing to do with ST - so you need to contact Hope RF for support with it.
A complex system that works is invariably found to have evolved from a simple system that worked.
A complex system designed from scratch never works and cannot be patched up to make it work.
