AMP is server hosting software, not a server host itself. It runs on your equipment. As such, it is your responsibility to open your network so that others can join.
In short, you need to port forward the Minecraft game port (25565) so that others can join your network externally. Alternatively you can use a tunneling service like playit.gg but it is more complex. Google is your friend with port forwarding. Find the model of your network router and google its name + “port forwarding”.
