I just bought a toyota innova g a/t. My previous car is a corolla gli a/t. My questions relates to the following gears: D, 2 and L

During the test drive, the toyota agent told me that even if the car is climbing a steep road, the stick shift should stay at D. 2 and L are for downhill driving. His he correct? I'm confused since with my corolla gli a/t, i use D for normal plain road. While 2 for steep road. I have never used L, sine I do not know what that is for.

Please clarify me on this matter. Thanks in advance.