I duplicated the demo database as shown in video.
I got an error when running about Melee Body not being in the current database. I found "Body" prefab in the Demo folder and it was referencing Body of the demointegration instead of my new database.
I fixed the reference, and then right clicked on the Demo/Prefabs folder and converted it to use my new database in case other things were not fixed.
Hitting Play, my demo scene runs without errors
I got an error when running about Melee Body not being in the current database. I found "Body" prefab in the Demo folder and it was referencing Body of the demointegration instead of my new database.
I fixed the reference, and then right clicked on the Demo/Prefabs folder and converted it to use my new database in case other things were not fixed.
Hitting Play, my demo scene runs without errors