I created a server using an upload of my single player world. But whenever I first connect to my server, I spawn in the default world that the server first generated, and I have to type /worlds and click on my world every time I log on. I can enter the nether fine, but exiting through the same portal puts me back in the default world. How do I delete the default world so that the only "worlds" are my downloaded overworld, the nether, and the end? Or is there a setting I need to change?