Pattern 1 extension is an extension of the minor pentatonic scale pattern (pattern 1) which you already know. This extended pattern is commonly used for improvisation. Note the arrows indicating ascending or descending slides.
Use the ascending slide on the way up the pattern and use the descending slide on the way down.
Practice playing pattern 1 extension in different positions on the fretboard and use it to improvise over the Jam-Along progressions at the end of the CD (page 63). Even though the above example commences on the 3rd fret, the pattern 1 starting note (for determining what position to improvise against a progression) is still the note on the 5th fret of the 6th string, so the pattern is still centred around the 5th position.