Dont work with Mac/Ipad etc but networking principles are the same for all devices. I dont really understand the wording (supernet or higher net) be I am guess you mean local LAN and Internet or a mixture of both.
1. To use a device on one network (subnet or otherwise) you need to be able to talk - there are a number of ways to do this - but in essence the devices or routers need to know about how to get to the subnet. On the Internet its DNS/Routing job - former converts human naming to computer addresses, the latter maps the "road" to the device. Using VPN on the Internet can also "Open Up" closed networks by creating a "direct Path" to local nework which is normally behind a router when the Internet is involved. So first thing is PING the address using its IP address - do you get a OK reply. If yes most complicated work already done - if not you will need to do more work which I am no going to get into here.
2. The port number is not unique by itself but is when used with an IP address (or DNS name e.g. indilib.ord) so the combination of destination address and port number point ,normally, to a specific computer/nework device - e.g. 192.168.1.12:7624 (Indi devices expect you to provide them in separate box's) would point to a specific device where indi would expect Indiserver to be running. However if you cant "talk" to the device it will never worked - so get (1) the ping working first.
3. If the Internet is involved you will most likely have 1 or more "Firewall's" - they normally block any traffic to unspecified port numbers (so port 80 ok as its used for surfing - 7624 could be blocked). So they have to be "unblocked" by telling the firewall you want traffic for this port to be allowed thru. It's a lot more complicated and there are other factors involved.
This article provides a "how to" for simple neworks (i.e. all on the same network/subnet)
indilib.org/support/tutorials/159-indi-on-multiple-devices.html It uses HOSTS file to provide what DNS would normally do - convert Human names ,e.g. STARPI, into an computer address 192.168.1.50.
You will need to provide more info to get a better set of instructions maybe this may help
www.steves-internet-guide.com/basic-networking-course/
Sorry if you already know this
As for he Web manager read this
www.indilib.org/support/tutorials/162-indi-web-manager.html