Hello Domenico,

I'm not sure what specific lessons cover blues scales but... if you know the pentatonic scales you will not have any trouble learning the blues scales. 

The blues scale adds 1 note to the minor pentatonic scale. The note is called a flat five [b5].

In position 1 of the minor pentatonic scale... for example A min pentatonic... the lowest note is on the 5th fret [A] the next note is on the 8th fret [C], next is the 5th string 5th fret [D]... at this point comes the blues scale note the 6th fret 5th string [Eb [also could be called D#]] then continue with the minor pentatonic...when you get to the 3rd string add the note on the 8th fret [Eb [or D#]] 

So...

Here is the A minor blues scale position 1...

• 6th string - frets 5-8
• 5th string - frets 5-6-7
• 4th string - frets 5-7
• 3rd string - frets 5-7-8
• 2nd string - frets 5-8
• 1st string - frets 5-8

My description only covers the 1 position. This blue note can be added to each position for the minor pentatonic scale. 

I think Robert will be able to point you to a more complete lesson/discussion of the blues scale.

Take a look at this one - https://www.masterguitaracademy.com/course/beginner-blues-solo/

It's the must-know scale for blues playing. It's the pentatonic scale with one note added, so now you have 6 notes instead of 5.