the note name edison says is the key is actually just a single note
most scales consist of 7 of them before repeating
so for example you are in the key of A natural minor
the notes are A-B-C-D-E-F-G and then repeated
If edison says your note is E, this is fine to use in the key of A natural minor as it is the 5th note of the scale and would likely appear as a root of either Em or E7, it is also the 5th of the A minor chord (A-C-E), so would work in the same way that timpani hits were usually root and 5th at one point in the distant past
If it said your note was F# then you would have problems using it A natural minor