I can't seem to find it in the Heroes 5 map editor. I place units and heroes on the map and then try to find a way to select them to edit them, and I can't for the life of me find out how. I've never had this basic of a problem with a map editor, before >.>
Once the object is on the map just click on it and then space-bar. If it has properties that can be edited you will see some then, however you may have to look deeper into the files.
Select "View" and then open the "Map-Properties Tree". There you will see the map's overview and also if that is open; you can then click on an object for more options. (if there are any more)