Oh.
In that case, IMO you just need to do this:
New Blueprint of ACTOR class.
Add static mesh component. Make sure it’s movable.
Add a cube static mesh.
Save.
Add a Box Collision component.
Add event “On Begin Overlap”
From the “Other Actor” pin of the Begin Overlap, click drag into empty area.
Now type ==
Select your Box from the pull down menu.
Add a BRANCH
Connect the red pin from the == to the red dot in branch.
Connect the execution pin from overlap to the branch.
Connect TRUE to Open Level.
Now place this invisible trigger wherever you want the box placed.
The moment it overlaps and it detects the box you will change levels so make sure the box isn’t too big.