On the iManage tab, in the Co-Authoring group, select Co-Authored Documents. 
The Co-Authored Documents dialog opens. The documents, which are shared with you for co-authoring and the documents that you have shared with other users for co-authoring, are listed in the left pane.

Select the required document in the list. The right pane displays the online view of the selected document and the various co-authoring options.