It’s my understanding that the word “inversion” in this context is just a fancy way of saying “different ways to make the same chord.” Honestly, the idea of theory is pretty new to me, too. I’ve only recently started getting really serious about banjo, so I’m kinda green, too.
Here’s Alan Munde’s Fretboard Geography lesson where he and Ben talk about the different inversions where Alan calls them 1, 2, and 3. It’s great stuff that I listen to in the car from time to time to keep it fresh in my mind.
https://banjobenclark.com/lessons/fretboard-geography-part-2-banjo