(1) The major scale, starting with C major
- which is all the "natural" notes (white notes of the piano).
I recommend starting with one octave in open position:
This is the notes C-D-E-F-G-A-B-C. It's not only useful for learning note positions, but also the sound of the major scale ("do-re-mi-fa-so-la-ti-do"). I also suggest singing it as you play it. Sing the note names, or "do-re-mi...", or "1-2-3..."
Play it down as well as up, and use the same fingers as fret numbers (index fret 1, middle fret 2, ring fret 3).
(2) Then expand it to the full open position pattern:
Notes (string by string) = E-F-G|A-B-C|D-E-F|G-A|B-C-D|E-F-G.
Again, play in both directions, and use same fingers as fret numbers.
(3) Play the same notes, but start and end on A (in both directions). This is the A natural minor scale
Listen to the difference in sound: minor is more moody or "sadder" than major.
You could then try leaving out B and F to produce the A minor pentatonic
This is a common improvisation scale. It's usually played as a full 6-string pattern higher up the neck, but this will introduce the sound to you.
From there, I suggest learning the G major scale, and how it differs (F becomes F#).
Scales are important as the basis of melodies, keys and chords, and are (therefore) the source of all our music. That's why I advise starting simple like this and understanding the sounds, before venturing into movable box patterns for soloing.