At least in terms of the physical act of landing, seaplanes and floatplanes land on the water pretty much in the same way that land based airplanes land on the ground.
They start with an appropriate approach airspeed, a slight flaring just before touching down, feeling it as the aircraft touches the water, and then it's slightly different. Because of the water's drag the aircraft will slow very quickly and settle into the water. Brakes aren't really needed. And that's good because they don't have any brakes that work in the water.
Once in the water they are as controllable as a boat. Which is to say, not that much. In fact, in the water they are navigated pretty much just like a boat.
Most if not all seaplanes and floatplanes have "water rudders" that allow them to steer in the water just like a boat. But as they approach a pier or beach you'll usually see the engine stopped and the pilot out on the float or leaning out of the aircraft with an oar rowing the boat to shore (sounds like a Peter, Paul, and Mary lyric).
If the question wonders why the aircraft don't sink, it's because they are designed to float.
Floatplanes are typically normal aircraft that have been outfitted with floats, usually two, one under each wing. Seaplanes, on the other hand, are designed specifically for water operations.
Many or even most floatplanes and seaplanes are what's called amphibious. That means that they can land and take off from both water and land. Typically they have retractable/extendable wheels (landing gear).
While it's important that an aircraft's landing gear has been extended when landing on the ground, it's equally important, if not more so, that the landing gear is retracted when landing on water.
The aircraft in the video is a "floatplane" with aftermarket floats.
This is a seaplane where the fuselage is designed to float like a boat. It also has floats, but they are part of the design.
This is a Piper Apache on floats. It's also the aircraft that I earned my Commercial Multiengine Seaplane rating in.
This post originally appeared on Quora. Click here to view.