Help for location for architectural interactive walkthrough

Hi guys im really clueless on how to do since a very beginner in unity. What my project is interactive walkthrough and i have my building and my question is example your starting point is on the ground floor and i want the next location to be just a few meters away and i want that location to be highlighted be in a circular spot and when ill go to that spot the next spot will be shown directly be it on the 2nd floor. do you guys have any idea?.im really sorry for the trouble just want to know how to do it or you can give me advices. a really big thanks

 

Why not add a flat slope (quad with collider to the stairs).
In the unity editor import standard assests fps character
drag the prefab into the scene.

This will then give you a character to walk around the scene. Both floors.