Begin with the thumb of the left hand on middle C. In the first measure we step down from middle C (line) to B (space) to A (line), to G (space) to F (line). Your 5th finger (little finger) is on F in the bass clef.

In the second measure, the 5th finger is on F (line). Step up to G (space), then up to A (line), up to B (space) and back up to middle C (line).

Count 1,2,3,4 as you did in the previous songs.