It is best to pick the strings with your fingernails as this gives a better sound. Grow your fingernails to a comfortable length for your playing with attention to the following points.
The free stroke is the picking of a string with a right hand finger when the finger moves freely away from the string after it is picked. The finger picks the string then bends slightly into the palm of the hand. The finger will move across the adjacent string.
The left hand fingers are numbered as such.
The letters p, i, m and a are used to indicate the right hand fingers.
p (pulgar) - thumb
i (indicio) - index finger
m (medio) - middle finger
a (anular) - ring finger