To make it easy on you I have included two methods to initiate a Level Sequencer cutscene. There is a Quest Event to play cutscenes when the state of a quest changes to a specific state you define, and there is also a way to play a cutscene when the player interacts via an Interact Quest Objective.

Tags are used to reference the Level Sequence in your level and there is a helper function that will find, play, and create a UI to let the player cancel the cutscene. You can find that helper function in the Blueprints/Variables/ folder inside of the BPFL_SharedFunctions.