There  are a lot of scales in guitar. Now we talk about some of them like  normal minor scale, normal  major scale, harmonic minor scale, harmonic  major scale, melodious minor scale, melodious major scale, diatonic  minor scale, diatonic major scale, pentatonic minor scale, pentatonic  major scale, augmented scale, diminished scale, blues scale, nu-classic  scale, Arabic scale, box scale, Dorian mode, the Phrygian mode, the  Lydian mode, the mixolydian mode etc.
Natural minor scale  (key of A)  
Root note on sixth cord. first  you  have to play sixth cord A note on fifth fret then sixth cord B note on  seventh fret then sixth cord C note on Eighth fret. Next play fifth cord  D note on fifth fret. fifth cord E note on seventh fret, fifth cord F  note on Eighth fret. Then forth cord G note on fifth fret. forth cord A  note on seventh fret.
natural major scale (key of A)
Root  key on sixth cord. To play this scale you have to play  sixth cord A  note on fifth fret . sixth cord B note on seventh fret. Then fifth cord  C# note on forth fret. fifth cord D note on fifth fret. fifth cord E  note on seventh fret then forth cord. Forth cord F# note on forth fret.  Forth G# note sixth fret. forth cord A note on seventh note.
Box scale (key of A)
Root  key on sixth cord. To play this scale you have to play sixth cord A  note on fifth fret . sixth cord C note on Eighth fret then fifth cord D  note on fifth fret. fifth cord E note on seventh fret.Next forth cord  G  note on fifth fret. forth cord A note on seventh fret. then third cord C  note on fifth fret third cord D note seventh fret. then second cord E  note on fifth fret. second cord G note on Eighth fret. then first cord A  note on fifth fret. first cord C note on Eighth fret.
Blues scale (key of A)
Root  key of sixth cord. To play blues scale you have to play sixth cord A  note on fifth fret. sixth cord C note on Eighth fret. Then fifth cord D  note on fifth fret. fifth cord D# note on sixth fret. Then fifth cord E  note on seventh fret. Then forth cord A note on seventh fret. forth cord  G# note on sixth fret. forth cord G note on 5th fret.
Arabic scale (key of A)
root  key on sixth cord. To play this scale first play sixth cord A note on  5th fret. sixth cord A# note on sixth fret. Then fifth cord C# note on  forth fret. fifth cord D note on 5th fret . fifth cord E note on seventh  fret. fifth cord F note on Eighth fret. Then forth cord G# note on  sixth fret. forth cord on seventh fret.
