A [[Blueprint Class]] may have a Construction Script. This is similar to a C++ constructor in that it is run when an instance of the class is created. The Construction Script is a tab next to the [[Event Graph]]
A Construction Script is implemented as a [[Blueprint Visual Script]], very much like any other [[Blueprint Function]].
Remember to call the Parent Construction Script. If there is no node for the Parent Construction Script then create one by clicking the Construction Script start node and select Add Call To Parent Function. It is often a good idea to call the parent's Construction Script even if it doesn't do anything because it might do something in the future.
There is a tab in the [[Blueprint Actor Editor]] for the Construction Script. The tab can be re-opened by double-clicking My Blueprint panel > Functions > ConstructionScript.
By default the Construction scrip is run continuously when an Actor Instance is dragged. This can be disabled by unchecking Toolbar > Class Setting > Blueprint Options > Run Construction Script on Drag. The construction script is not run when a [[Scene Component]] within an Actor Instance is dragged.
A [[Property]] edited from the Construction Script becomes marked as [[User Construction Script Modified Property]], or UCSModified for short.