This Unreal Engine 5.4 video is about selecting a Tower with the Mouse.
We start by creating a Blueprint Function Library for our Tower Under Mouse/Cursor logic, because duplicating code is generally a bad idea. We then call that code from the Tower Manager, and add it to the Player Blueprint. We create the Select Tower and Unselect Tower functions, which based on Left Mouse Button, will call the Select/Unselect function on the appropriate Towers.
https://dev.epicgames.com/community/learning/tutorials/EPPj/unreal-engine-13-tower-selection-let-s-make-a-tower-defense-game