One of the advantages to having a network is that you can put documents in shared folders and open them from any computer in the network. For example, you might put all your important work documents in a shared folder on your main work computer. If you also have a portable computer you can use outside on sunny days (or from the sofa on lazy days), you can work directly with those documents from the remote computer.
The process is really no different from opening a document on a local computer. You could, for instance, just navigate to the folder, via the Network folder, in which the document is stored. Or, open the Computer folder, type the UNC path to the shared folder in the Address bar, and press Enter. Then, double-click (or click) the document you want to edit, and the document will open from the remote computer (providing that the local computer has the appropriate program installed for working with that type of document).
Optionally, you can go through the program’s Open dialog box to get to the document. Here’s how: