When I have two elements overlapping–for example, two images, one in one row, the other in the row below it–how do I assign which one will lay on top of the other?

Thank you for your question.

Unfortunately we do not have any controls currently in the Post and Page Builder to allow you to change the z-index value of page elements to handle overlapping elements.  I have created a feature request with our development team to consider adding this feature to a future update.

I hope that we will be able to get this control added soon and please let us know if there is anything else that we can do to assist you.