Try this:
Make the "Freight Train" C chord. That's a C chord plus your little finger on the third fret of the first (i.e. treble) string. Hold the chord throughout this exercise.
1. Play the fifth string with your thumb, and the first string with your middle finger at the same time. THIS IS THE ROSETTA STONE OF FINGERPICKING.
2.Play the second string with you index finger.
3. Play the fourth string with your thumb.
4. Play the first (treble) string with your middle finder.
5. Play the fifth string with your thumb.
6. Play the second string with your index finger.
7. Play the fourth string with your thumb.
REPEAT REPEAT REPEAT. Good luck. The rest is all variations