The 5-40 is a four engine, large, commercial airliner produced by the Lonestar. Very easy to take off, easy to fly, long range, however landing is a bit different to how many other planes would land...

How To Takeoff:
Full throttle, flap slider fully down, and it'll take off when it's ready (which is pretty quickly). If your taking off from an odd location, you can raise landing gear before the plane begins to climb, and it'll trigger a climb, but it's a riskier manevuer.

How To Land:
Firstly, you need your engines on, around 30%-40% throttle I suggest, flaps for all the way back on the slider, Get a low altitude, preferably a fair way before the landing strip.
Now, right before touchdown, cut the engines, try not to trigger the air brakes too much, then when your actually on the runway, full braking. Make sure the touchdown is gentle, and as close to the start of the runway.
It can take a bit of practice to land, have a go a few times.

Now, you may be asking about the bouyancy. It can safely land on water, and move about in the water, however, takeoff from water is pretty hard, if not impossible.