Licensing becomes an issue when you open files, not when you create them. Therefore, you need to make sure that the Desktop Clients are licensed or you won't be able to open files created on another computer. To license the Clients, just open a file from the server (File --> Open in Server). You can then immediately close the file, and the Client will remain licensed for 30 days thereafter. You just need to relogon to the server once every 30 days.