Begin with the thumb of the right hand on middle C with a red dot (line). Step up to D (space), then up to E (line), up to the next key F (space) and on up to the next one, G (line). Your 5th finger (little finger) will be on G.
G is a white note with no stem. We call this a whole note and it gets all 4 counts in 4/4 time. In the 6th measure we have two G's that are white notes with stems (half notes). Each of these notes gets two counts.