The first one I built was simpler using a LILYGO TTGO T-Beam:

https://www.aliexpress.com/item/4001178678568.html (pick the correct frequency)

This module is complete and just needs a 18650 battery. I used this case for it:
 
https://www.printables.com/model/127253-t-beam-v1x-case-for-meshtastic