On Windows, you can either specify a UNC path (make sure you have the rights to read/write from the path) or 'map' the network storage to a drive. Here's how to map a network drive on Windows XP, here's how to do it on Windows 7. and here's how to do it on Windows 8
On Mac, use Finder to Connect to Server. Then check the /Volumes folder for your network drive.
Finally, on Linux or Mac, you can mount the network storage to a location on your filesystem.
Once the storage is 'mapped' or 'mounted', you should then be able to find it by using the 'Browse' button.
Any other FAQs I forgot or clarifications required? Post your ideas below!