This guide is just for hosting locally. If you want to host to the outside internet you also need to do port forwarding on your router. So that when someone con

This guide is just for hosting locally. If you want to host to the outside internet you also need to do port forwarding on your router. So that when someone connects to your outside IP your router relays that to the pi specifically. It's not super dangerous, just make sure you keep everything updated (your linux OS, your server software). And make sure that you only open the ports you need to.