Sharing data file simultaneously

Hello, how can my client share thier "sage 50 pro" data file with me (I have the accountant edition of sage 50), so i can work on thier file remotely? And simultaneously? Also, is there a link and/or video that discusses the information to show the client who is considering this option (benefits and custimization options for allowing or denying access to certain parts of thier file? Thanks Slight smile would be helpful so my client can discuss the options with thier board of directors.