Here is a diagram for a Bb scale – first position. (First position means that you are staying in the first part of the neck, near the nut. Actual scales go all over the neck, but let’s just start easy, shall we?)
Starting on a low note, the first note of the scale is a Bb – 3rd finger on the 3rd fret of the G string. Then:
Open C string
2nd finger on the 2nd fret of the C string
3rd finger, 3rd fret of the C string
1st finger, 1st fret of the E string
3rd finger, 3rd fret of the E string
Open A string
!st finger ,1st fret of the A string – that’s the top note of the Bb scale.
I have included some optional notes – circles filled with grey. These are also part of the Bb scale, but are above or below the full scale I described.
Doodle around with this and get used to it. Play it over a Bb chord, or a Cm, or it’s relative minor: a Gm.
This would be a good scale for songs that have Bb, Eb, and F chords.
Thanks Jeff, for asking about this.