Hey Travis. C7 means the 7th would be flat. Every time you would see that scale, you would want to use the Bb blues

this sounds confusing. let me see if I get this straight. I'm no go with scales, (the names.) I should work on that. Bb starts with G on alto. i think. so the seventh note...G? is flat? that is confussing, because the first one wasn't flat... nevermind.

The basics of Chord symbols are fairly simple but will be difficult unless you know your scales. Although there are a variety of symbol conventions they all have the same basic rules. The letter designates the root of the chord. Unless noted otherwise the chord is major. If there are two letters seperated by a slash (C7/E for example) the second letter is the bass note. There are four chord types Major=C or CMaj=C E G (Maj 3 Perfect 5) Minor=Cmin or C-7=C Eb G (min 3 Perfect 5) diminished=Cdim=C Eb Gb (min 3 Diminished 5) Augmented=Caug or C+=C E G# (maj 3 Aug 5) Numbers represent chord tones above the root. For notes other than the seventh the interval unless altered is major or perfect. So assuming C as the root 2 or 9=D (major second) 4 or 11=F (perfect fourth) 6 or 13=A (major sixth) The seventh is special case. The minor seventh is played in most cases. The exceptions being chords designated maj and dim. With C as root CMaj7=C E G B (assumes major seventh) C7 =C E G Bb Cmin7=C Eb G Bb Caug7=C E G# Bb Cdim7=C Eb Gb Bbb (assumes diminished seventh here's one origin of the mysterious double flat...) You can alter any tone with sharp or flat so CMaj7 (#11) is C E G B F# Cmin7 (b5)=C Eb Gb Bb Caug7 (#9)=C E G# Bb D# C7 b9=C E G Bb Db and so on. I think that is about all you need to know to decipher most chord symbols.