Every user that wants to make modifications to the model must first connect to it.

On the Advance steel ribbon,
Extended Modeling
tab >
Multi User
panel, click
(Connect to Master model) to connect to the Master model.
The Master model is loaded into the workspace and is displayed in read-only mode.

The model that is loaded into the workspace is a local copy of the Master model. The AutoCAD® Save command saves the local copy on the local computer. To share any modifications with other users, the modifications must be published in the Master model.