I can successfully access the app using a private IP and the default port used in shiny-server. I would like to know how to make it accessible to people from outside the network. I have my public IP but I don't know what the corresponding port is. Can you help me accomplish this?
You need to configure port forwarding in your router so traffic from port 3838 gets redirected to your server IP (or port 80 if you have configured a reverse proxy). Each router brand and model has a different user interface so I can't give you detailed instructions.