Question about Driving Positions?

In both P and N, the transmission is disengaged from the engine. The vehicle will easily turn on (engage the starter) in either position. P, the drive wheels are locked and will not easily move if pushed. N, the drive wheels are disengaged, and can easily be pushed. If the vehicle is being towed, often it needs to be in Neutral, N.

The two Low gears are for traversing slippery surfaces at low speeds, or when driving on a hill, where traction can be helpful to hold back the vehicle, instead of using brakes or going up a steep incline. They will force the transmission into low or medium gear, instead of using automatic selection in D, based on the speed that you are traveling.

Park engages the parking pawl. The vehicle won't move. Neutral separates the transmission from the engine. The car can be allowed to move as if on a hill, but not with engine power. Low are low gears. They translate engine power into movement, slower movement with more power.