This is a closed-position exercise in IInd position. It uses four-finger left-hand positioning: All the notes on the 2nd fret are played using the index finger, all the notes on the 3rd fret by the middle finger, and so on.

Strive to play evenly, and use the fingers behind the middle, ring and pinky fingers to help as needed. Don't lift your fingers to far off the neck, and make sure to alternate your right hand fingers (or if using a pick, the direction of picking).