The word "pentatonic" comes from the Greek word pente meaning five and tonic meaning tone. Simply put, the pentatonic scale consists of five notes within one octave, that's why it is also sometimes referred to as a five-tone scale or five-note scale.
Nowadays the pentatonic scale is mainly associated with rock and blues, however it is believed that the pentatonic scale was used way back in ancient times. Composers like Claude Debussy & Beethovan have used pentatonic scales for added effect in their music.
The major pentatonic scale is scale degrees 1, 2, 3, 5, 6 of the regular major scale. You'll notice that it's a major scale without degees 4 and 7. When you remove degrees 4 and 7 from the major scale there are no more half steps; for this reason pretty much any note in the major pentatonic scale sounds good over a major chord progression.
The pentatonic scale has no semitones (ex. c–d–f–g–a–c} this is the most commonly used form. This is classified as the anhemitonic scale
The two basic forms of pentatonic scales are:
Major Pentatonic - Consists of the 1st - 2nd - 3rd - 5th - 6th notes of a major scale.
Minor Pentatonic - Consists of the same 5 notes of a major pentatonic scale but its tonic (first note of the scale} is 3 semitones below the tonic of the major pentatonic scale.
For example, the C major pentatonic (C - D - E - G - A} has the same notes as the A minor pentatonic (A - C - D - E - G} but arranged differently. The first note or tonic of the A minor pentatonic scale (=A) is 3 semitones (half steps) lower than the first note of the C major pentatonic scale (=C). It uses the 1st - minor 3rd - 4th - 5th - minor 7th notes of a scale.
Now let’s see what the C major Pentatonic scale would look like on the Fretboard.
In this position we start the scale on the lowest note of the scale this being the note of C
We can also play the scale starting from each of the 5 notes in the scale each time starting on the low E string playing 2 notes per string.
See example below when we start the scale from the D note of the scale.
We now have 5 different scale patterns starting from each of the 5 notes in the scale.
Each pattern gives us a new position in which we can play the Pentatonic scale and these are numbered 1 – 5
For some scales it is better to play the position lower on the fretboard below the initial root note.
Here are each positions in order, note that we can also play the position below the original C on the 8th fret of the fretboard.
Conclussion,Learn each position one at a time, have a backing track use each position to improvise over. Then start to combine the position. I would advise that you start with just using 2 postions the increase to 3 and so on untill you are moving freely around the fretboard using each of the position in a seemles manner.