Setting up Remote Desktop users - searched but could not find

I am setting up 4 users to remote into my server to access Sage Mas 100. I know there is a way to have them log in and have the program start automatically, but I can't seem to find it. Can anyone help? 
See below image...i need help figuring out what string to put on the "Program Path and File name" box, and the "Start in the following folder box"... I want the user to only see the sign in for Mas, not the entire desktop on the server.