Motion between and within slides is genuinely useful in small doses, and distracting in large ones.
Transitions tab — applies to how one slide changes to the next. One simple transition applied to every slide reads as more professional than a different flashy one on each slide.
Animations tab — makes one object appear, move, or disappear on its own within a slide. Useful for revealing a list of points one at a time instead of all at once.
Less is more
Overusing animation is the single most common thing that makes a student presentation look unpolished. Used sparingly, it's not noticed. Used everywhere, it's all that's noticed.
The Animation Pane (Animations tab → Animation Pane) lists every animation on a slide in the order it plays, numbered — drag an item to reorder it. A trigger makes an animation wait for a click on a specific object instead of playing automatically in sequence.