How to add levels together and add switches for exploring new ones?

Hello everyone, hope you all are having a nice day.
Let’s say that I want to make a map that is the hub world, and then another where the actual action happens, without making it all one big map (if that’s possible), but I also would like the player to have talked to some people before they access this area. How would I go about doing this? I’m thinking something like RPG Maker where you select and area or an object, and interacting with it puts you in the corresponding place in the other map.
Sorry for noob question, I couldn’t find it anywhere.