Moin wanted to know how you can change the world at mc host, but it is important that the player keeps his items in the inventory from the previous world?
There are a lot of videos on youtube how to do that, but for the players to want to keep their stuff, you have to put your own plugin on it
You keep your items automatically
You only change the world and not completely everything
But if you want you can download the playerdata file to be on the safe side and upload it again after changing the world