To show the thumbnails of the photos in an album, use shortcode
[wppa type="thumbs" album=".."]
The album specification may be an album number, an album name preceded by a dollar sign ($), an enumeration of album numbers or any kind of virtual album identification.
This example is made by shortcode
[wppa type="thumbs" album="2.4"], meaning: the thumbnails of albums 2 and 4 together. The sort order is (because it is not just one album) as specified in Basic settings -> Misc -> I: Miscellaneous settings -> Item 2: Photo sequence default.