Hi,
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.