(D) normal driving
(S) sport mode. It just holds the cars engine speed at higher rpms for quicker response.
(B) low gear ratio which can be used to the get car started moving up hill but u can't go very fast on it. A safe speed is like 30mph and this can also help you to slow down at highway speed.
It's normal for the car making a lot of engine noise due to its trying to keep enough power to go a hill.
That is going to be a common complaint with vehicles in this price range, especially those equipped with CVT's. It is just trying to make the most of its Briggs and Stratton sized engine in a 2800-2900lb car by keeping the engine in its powerband. Cars in this price range with the exception of the Focus are also built to a strict price and thus sound deadening related things are sacrificed.
I believe B is for brake and used to go downhill. S is sport and makes the transmission "sportier" so best bet would be to just leave it in D. A CVT is designed to always keep the engine at the best rpm for the task at hand, the transmission will adjust accordingly.
I had similar thought, but i was probably carrying noticeabley larger weight, so i kept overdrive back on due to elevation and engine strugling up hill.
But never thought of using S and B mode. What is it's purpose?