Using the Process Instance List Web Part

By clicking on process name, the Web Part will show a menu with actions that the user can perform (e.g. if the user has privileges to cancel a process, this action will be available).

The Show Data action will be available if a process instance is an InfoPath-based process template, SharePoint Form Library is Web Browser enabled and associated InfoPath has a view named ROView (Read Only View). There is also a Go to Source action that opens the Form/Document library. You can perform some global actions over one or more process instances by checking the check boxes on the left and clicking on Global Actions.