The betacast application is independent and you need to install at least two copies of the application. For example: for streaming on first device and for viewing on second. The streamer configuration includes only two mandatory parameters: IP address and UDP port
If you want to use connection over Internet you should be familiar with base principles of networks and have experience with UDP port forwarding on your router. The streamer uses all found network interfaces as incoming and you have to manually make UDP port forward on your network router to provide over Internet connection.
If you have some kind discovery or connectivity problems you can review Router Setup section.