Is the computer node showing in the left sidebar?
If so, right-click on the header ("computer") and select 'manage folders.'
From there you have a few choices including 'add network share' and 'choose filtered folders.' If you have a drive letter assigned to your networked music folder, make sure it's selected in the 'choose filtered folders' section. You can then choose whether to show -all- folders or just the filtered folders.
If the computer node is not showing go to Preferences > Layout (1) > left sidebar > and select the nodes you want to appear in the left sidebar.