What function is this?

I’m trying to recreate the functionality of the UE4 Arch LOFT “game” and have struck a wall (actually several but…)
I cannot figure out what this function refers to or how to create it? (Highligted in Yellow) - i’m trying to reverse engineer it from studying it, but at a loss now…
If anyone could enlighten me, I would be much appreciated.
Just to clarify “Mostrar” means SHOW in spanish.

Do you see “Goto Definition” when you right click it? Should take you right to the code

Its a self defined Function inside a Interface.

https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/Types/Interface/index.html
https://docs.unrealengine.com/latest/INT/Engine/Blueprints/UserGuide/Types/Interface/UsingInterfaces/index.html

Nothing Special and used pretty often.You should be able to find lots of ressources about Interfaces.