First create a blueprint interface
Then under class settings add the interface, they will now send “messages” between each other
From the character do a line trace and call the blueprint interface you made on the hit actor if it has it itll execute whatever code is attached
Example most people call the BPI(blueprint interface) “interact”
So when you “interact” with a door by hitting it with your line trace and calling the interface itll open the door, usually with a timeline… but you may also use that interface on a crafting table for example and have a crafting UI pop up…
Neadless to say whatever video youve found that is recommending you use a plugin, is not a standard plugin it will be a purchased asset, beacuse they are trying to sell you something… a door should be super easy and no need to buy it unless you want the door to look a certain way and dont wanna make it yourself,