Actually, we started out with a picture of a prop that we had to create a custom model for. (The hanging Chromabulbs.) We used the built in model maker. Very nicely done.
Once we made the custom model, it turned out that we had a lot of things to do to make it all work out. Using the standing version xModel (downloaded from the Facebook group) we were able to compare all the items that were in that model to what we didn't have.
Using this method, we learned a LOT about what needs to be done. "Manually typing up a .xmodel file" may be in the next round of learning. Who knows. I'm just very happy with what we are learning in this round.
BTW - I have been exporting the model (that danged 'right click' thing again) and then bringing those models back into the layout as copies. Working like a charm.