The G major pentatonic scale is one of the most common scales used in bluegrass music. "Pentatonic" refers to a 5 note scale pattern and in this particular scale, we're starting on a G note. It goes from your 3rd fret, 6th string all the way to your 3rd fret, 1st string. You'll be using your index and middle fingers only in your fretting hand and the scale consists of open strings and notes on the 2nd and 3rd frets.
For this lesson, use downstrokes only so you can focus on nailing the left hand fingering.