Once you have your server started on a specific port, the first thing to test can be on http://localhost:port. You can use any port you like. Just don't use common ports which could be in use by other applications.
If your localhost is working, you can try if you can connect to your server from the outside world, from an external location. To provide this, you will need to setup a PORT-FORWARDING on the router or modem that is in use. The configuration of this depends on the brand of the router in use.
Fixed IP address?
If you or your customer has no fixed IP-address, you can use a service as dyndns. Even if you have a dynamic IP-address with your internet connection, you can simulate a fixed address with these services. A lot of routers has this build in. You can setup a specific name you want to use for your server, and the router will communicate with the dyndns server so your dynamic IP-address will always be published.
Some of these services are free, others have a yearly cost.
Cloud server?
The choice of putting your application in the cloud on a server as Amazon, Microsoft Azure, ... is up to you, and has nothing to do with BOA. You can use your own internal server, or even a standard PC, as your own private server. As soon as BOA can reach the server via a static IP-address, or a static URL, you are ready to start.
