How can I search in the Publisher?

You can search for a folder or a diagram element by name by just typing this name (or a part of it) in the Search publication box on the top of the Publication pane, Under review pane or Archive pane.

When you type a text there then only elements with the name containing this text will be shown in the publication tree plus all folders that contain these elements.  Note that the search in the publication will be done on both the current name and the original name. For example,

The General processes is shown here because it contains the Marketing process.

The search is done on both the current name of the published diagram version and the original name of the diagram.

In the same way you can search for a diagram in the Under review and Archive panes.