Intranet usually means over a local area network while internet means linking via the internet. Not sure which you need here. Intranet is very simple. You install the software on two machines connected to the same LAN, open the files on the server and use Open Remote... to bring up such files in a list where you can select one to open from FileMaker Pro.
If you mean over the internet:
Yes, this can be done.
You'll need to configure firewall and ports correctly--see the documentation that comes with server.
You may need to set up port forwarding on the internet router that connects your server to the outside world.
You can then launch FileMaker on a different computer that is also linked to the internet and use Open Remote..., entering the correct IP address to find and open the hosted file or file(s) on your server.