Select multiple slides in slide sorter view
1) To move to Slide Sorter View, select the 'View' menu and select 'Slide Sorter'.
2) Press and hold down SHIFT.
3) Click each slide to be selected. (Each slide is highlighted when it is selected.)
NOTE: Make sure to keep the SHIFT key pressed.
4) When all the desired slides have been selected, release the mouse button and the SHIFT key.
5) To deselect the slides, click anywhere else on the screen.