Scale diagrams are like a snapshot of your guitar’s fretboard showing 5 frets. The black dots show the scale pattern as it appears on the fretboard. The numbers in the black dots show what fingers you should use to finger that note when practicing the scale. The white dots at the top are open strings.
Below is the G (pentatonic) scale pattern. It’s in open position. You’l notice that all six open strings are notes in the scale. To play this scale, start with the lowest note and play each note, one at a time in ascending order, and then back down again.
The numbers are the suggested fingerings. Since half the notes in the scale pattern are open strings, fingerings are quite simple.
While this may look similar to a chord diagram, it’s not played like a chord. You should practice playing it one note at a time. Start with the lowest note on the low E string and play up the scale until you get to the highest note, then go back down backwards.