C

C/B bass

Am

Am/G bass

F

G

C

G7

In following the descending bass line (C - B - A - G - F), the F chord is played by using a root 6 bar chord shape:

F

For further information on bar chords, see Progressive Rhythm Guitar. This book will also provide you with a large number of supplementary progressions for fingerpicking practice.
Pattern 7