Hi Jamal,
One of the easiest ways to get people connected to the desired Workflow Manager database is to take the connection JTC file and share it to all of the users.
To get the JTC file navigate to c:\ProgramData\ESRI\WMX\10.#\Database and there will be a jtc file for the name you have setup.
Copy that file into the same location on the client's machines.
Then in Administrator ensure that all new users are added and assigned to a group within the database.
Cheers,
Michael