How to include submodel into main model in LeoCAD? In LeoCAD I can create multiple submodels. But how do I merge them or integrate one into the other? The release notes suggest that this is possible, but I can't seem to find out or find resources about how to do it.

The idea behind this is that I would like to create building instructions for the model using LPub3D. I would like to use submodels to make the building instructions easier to understand. I would like to show how a certain part of the model is built and then at some point integrate it into the main model. So far I have not managed to do this. The different submodels coexist separately and in LPub3D I have only access to the main model (i.e. the first submodel).
I have now figured out that you can include submodels the same way as normal parts. In LeoCAD, go to the parts panel where you can select a category ("All Parts", "Parts in Use", ...), scroll to the very bottom and select "Models". Then you can select your submodels and incorporate them.

(For some reason, my submodels still don't show properly in LPub3D, but I guess that is a separate question.)