Watch the Parallel Exercises online guitar lesson by Andrew Leonard from Beginner Method for Classical Guitar
Here are three left hand exercises to begin building your classical guitar technique. The first exercise, using adjacent fingers, is explained along with the right hand considerations for all three exercises.
At 3:30 the adjacent finger exercise is played. Remember to play each finger combination as many as ten times (or more) before going on.
At 5:05, Exercise 2 - Three Notes Groups of Adjacent Fingers
At 6:15, Exercise 3 combines adjacent & non-adjacent fingers. Again, they're ascending & descending
As you practice these exercises, pay close attention to when to hold down and when to lift your left hand fingers. Doing so will help you begin to develop finger independence, a very important part of left hand classical guitar technique.
Lastly, remember to alternate I & M rest strokes to continue to develop this important foundational classical guitar skill and to synchronize the left hand and right hand.