If you have screened references, but they do not appear at the next Level of your review as expected, it may be due to your settings set for processing (Users Needed to Process) or those that determine inclusion of your references.
The first step in determining the cause would be to view the Reference Status Report. The Reference Status Report provides a real-time snapshot of the status of every reference in your Project. To view this report, go to Reports > Reference Status menu selection.
In this report, if your screened references appear in the "Some Reviewed" column, this indicates that the references have not yet been screened by the required number of reviewers. This is driven by the "Users Needed to Process" setting found in the Level Settings option of your workflow. Distiller will wait for the required number of users before including or excluding the reference.
If your reviewed references are appearing in the Conflict column, then your references are in a conflict state and the conflicts must be resolved before they can progress to the next Level in your Project.
The following link will provide additional information about the Level Settings.
Alternatively, references may not appear at the next Level on your Dashboard because you are not assigned to review at that Level. Your Project Administrator (or anyone with the Manage Levels permission) can add you as a reviewer at a Level.