Start with the server, where your music files reside. Make sure you know that machine's external internet address. Open the server by going to the MJ or MC tools drop-down menu on the menu bar and clicking on 'Server'. Make sure you're not blocking the access port (probably port 80 or 81). Also make sure that your personal firewall, like Zonealarm, isn't in the way.
On the client side, go to the dropdown menu at File, select Library Manager. That will open a window with a series of buttons on the right. Click 'Add Library'. Then insert the IP address for the server in the appropriate dialogue box, give that library a name, close that and you'll find your new library address in the Library Manager field. Highlight that, click on Load Library, and with any luck your server library will load into the client program. From there, you access and play files as you would on your home coputer.
Of course, both server and client must be running MJ or MC.
Depending on bandwidth, you may find that files over 160 kbps will buffer excessively.
One question, in the other that i can test, they've media jukebox v8, and i've v9. Will gonna work?
No. You'll need the same version on both server and client side.
HTH
Listening to: 'Departure' by 'Andrew Hill' on Media Center 9.0