I went through the free LoRa/LoRaWAN training from Semtech a couple years ago and it was very good at explaining how it works to non-experts.

https://learn.semtech.com/

IIRC, you might have to look up videos on thinks like OOK or preambles to understand those parts, but that's easy once you know what to look for and have the context of how it is used.