To work with a published map, open it in ArcReader. If you know its location on disk, you can navigate to it using Windows Explorer, then double-click the map. If you already have ArcReader running, you can open it directly within that session using the file browser.
Both ArcMap and ArcGlobe documents can be published as .pmf files for use in ArcReader. You can tell if the published map contains 2D (ArcMap) data or 3D (ArcGlobe) data by examining the published map file icon. When opening a published map in ArcReader, ArcReader will detect the contents of the published map and enable the appropriate functionality.