To show list items one by one in presentation, you have to change the animation order
of each list item.
First, display the specific slide:
Select the list items, that has to be displayed in one the one:
Click on Animations
and choose Appear
The numbers on the left side stand for animation order of each list item:
Click on Animation Pane
in Advanced Animation
section, to display the pane where you can change animation order of list items:
To change the animation order, click on each list item with right mouse button and choose Start On Click
The numbers on the left side of item list should look like:
When you start the presentation, the list items will appear one by one.