Here are the finger placements for each chord:
C chord:
* Index finger on the first fret of the B string
* Middle finger on the second fret of the E string
* Ring finger on the third fret of the C string
F chord:
* Index finger on the first fret of the A string
* Middle finger on the second fret of the D string
* Ring finger on the third fret of the G string
* Pinky (fourth) finger on the second fret of the C string
G chord:
* Index finger on the second fret of the A string
* Middle finger on the third fret of the E string
Am chord:
* Index finger on the first fret of the E string
* Middle finger on the second fret of the C string
* Pinky (fourth) finger on the third fret of the A string