I also had troubles as I saw no “Class” field in the Add Child Actor Component node, to indicate which Actor the component who spawn. It turns out you just have to take the Return Value and add a new node Set Child Actor Class to set the class of the child you want.
I made a function out of those 2 nodes, and now I just have to call that function (with some Relative Transform parameter) to spawn new Actors inside the Construction Script. They do get cleaned up and replaced with new actors on Actor changes in the map, as expected.
This is my function:
Note that Add Child Actor Component Target is self since the BP I’m defining the Construction Script on itself owns the sub-actors.
You also need to select the class you want in Set Child Actor Class “In Class”.
I still had troubles making this react to changes in the map, as it doesn’t react to BP instance child property changes, see Construction script on child actor doesn't execute when child actor component is moved and Construction Script only uses default values but I made it work with a custom property on the main BP anyway.