You want the player to move from one map to the other when he enters a area. Because this code is so basic I tell you how to change it from the example and how to create your own

Change it

the example blueprint is called "ChangeLevel1" and is in the folder

1. Click on it
2. Click on the node "Open Level"
3. change the level name to the level you want this actor to direct you. (Full Name)

Create a new one

1. Create a new Actor Blueprint
2. Click in the Component Panel
3. Add Component
4. Select something from the Collision Label
5. add the note Event ActorBeginOverlap
6. add another node called Open Level
7. out the level name to the level you want this actor to direct you in. (Full Name)

Note: Here are no neat effects or loading screens when you change maps but this should help you through the prototype stage at least-