Learn how the notes are specified on the treble staff of classical guitar music. The notes indicate the time duration of each sound. This is a special problem for the guitar because notes are set by placing a left-hand finger on a string and actuating the string with the right hand. Moving the left-hand finger stops the sound. Another problem specific to the guitar is that most notes can be played on more than one string, set by more than one of the fingers of the left hand and actuated by more than one finger of the right hand. Classical guitar music must be carefully worked out and memorized.
Memorize the notes in the first position --- the left hand covers the first four frets of the guitar --- and then learn them for all the higher positions. In the fifth position, the fingers are "assigned" to frets 5, 6, 7 and 8. The position you should be playing in at any specific time are marked by a "C" --- for capo, Spanish for head --- and the number of the position with a dashed line that continues as long as you are in the position. If the position is not marked, you should be in first position of transition between positions. Playing in the correct position is absolutely necessary to get the right sound. Sometimes, the positions are in roman numerals and sometimes the C is omitted.
Understand the finger and string indicators that are specific to guitar music. The fingers of the right hand are notated p, i, m and a for the Spanish words for the thumb, index, middle and ring fingers. The little finger does not usually actuate strings, but if it does it is denoted with an e. The fingers of the left hand are numbered 1, 2, 3 and 4 for the index, middle, ring and pinkie. The difference is to make it clear if the notation is for the left hand or the right hand. If a string is explicitly denoted --- the same note can be played on different strings --- the strings are numbered 1 through 6 from thinnest to thickest and the string number is circled to distinguish it from the code for the left-hand fingers.