Is there a way to store user data like documents folder deskstop folder pictures etc on the server? If not how can a user access their files from a different computer on the network?
The Mac equivalent of roaming folders are Portable Home Folders, which are an extension of Network Home folders. You would need to use Workgroup Manager to configure them, as the required bits of GUI sit outside Server.app. The Snow Leopard documentation for this feature is pretty much still applicable.
Check out chapters 7 & 8 of the User Management guide (PDF)