This Unreal Engine 5.4 video is about Gameplay Effects; what they do, and how they’re applied. Gameplay Effects are a Blueprint Class that is used to apply modifiers to Attributes.
We start by creating a Tower Attributes Gameplay Effect, and go over what each of the Duration Policies are. Instant, Infinite and Duration each have their own overlapping uses. Next, we talk about the Gameplay Effect Modifier, and apply three Scalable Float values to the Tower Attributes of Range, Fire Rate, and Damage. We then show a few ways of applying a Gameplay Effect. We follow up by creating a Damage, which is just a negative value to Health, Gameplay Effect, as well as a Damage Over Time Gameplay Effect. Lastly, we show that the Modifier can be applied using another Attribute, or by using Set By Caller.
https://dev.epicgames.com/community/learning/tutorials/XWj4/unreal-engine-03-gameplay-effects-let-s-make-a-tower-defense-game