Use the scroll bars, mouse wheel, mouse clicks or arrow keys to move around and select the picture appearing in the top "Active Image" region.
Any sorting done in the "Tags" tab automatically transfers to the "Select" tab. You can reorder individual thumbnails with right-click "Cut Image" and "Insert Cut Image". These only affect the thumbnails. The files on your hard drive remain unchanged.
Left-click clears shows the picture just clicked as the active image. Click the "Selection Box" in the upper left of each picture to select that picture for further processing, such as removing or hiding.
Ctrl-click keeps all previous selections and adds the picture clicked.
Shift-click selects all pictures between the last selection and the new selection. Any selections not between the last selection and current selection are cleared.
Ctrl-shift-click keeps all previously selected pictures and adds all pictures between the last selection and the new selection.
The Zoom slider adjusts the size of the thumbnails in the overview.
Menu "Select/Copy Filename" copies the active photo filename to the clipboard.
Menu "Select/Copy Selected to" copies selected photos to another folder. The copied photos remain in their original location. This helps quickly organize photos downloaded from a camera or an external drive with everything in one folder.
Menu "Select/Create Map Markers" adds map markers for the selected photos. Clicking the map marker selects and displays the photo.