This is the second topic of the Learning the Musical Dynamics lesson.
Left Hand Position and Technique
The most common and comfortable starting positions for your left hand mirror those for your right:
Your left pinky (also known as LH5) on the C an octave below middle C. The other fingers on your left hand rest on the nearest D, E, F, and G, respectively.
LH 5 moves down to G, the bottom line of the staff, and your other fingers move accordingly.