Aperture controls depth-of-field. In the first photo, I focussed on the near tree with my lens opening set to f/5.6. (It would’ve been better if I set it to f/2.8 to get shallower depth-of-field. I’ll redo the example another time.) The tree I focussed on is naturally in focus, but the trees behind it are blurry. In the second photo, I focussed on the tree further back behind it keeping the aperture at f/5.6. The tree in front is now blurry. In the third photo I reduced the aperture (higher f-number) and focussed on the front tree again. In this photo with the smaller aperture much of the photo is in focus compared to the previous two.
Shutter speed controlling motion blur. In the first photo I’m using a long or slow shutter speed of 1/20s. The water is blurred and creates a fast flowing, yet soft look to the waterfall. In the second photo, I’m using a very quick shutter speed of 1/8000s. The pearlescent droplets of water are suspended in the air.
