I'm currently trying to transpose songs from numerical notes(doremifasolasido) into fingerstyle guitar tabs. However, I have absolutely no experience in music, so I am now stuck because I do not whether notes in a song sticks to it's main scale or not. So, let's say a song is written in D major, with the chord progression D, F, G, and C(in that order).
example: song is written in D major, the chords along with the notes(in numerical notation) are D 1 3 3 5 7| F 3 4 4 2 | G 1 3 3 5
Now when the song changes chords(from D to F let's say), does the notes adjust themselves(from the D maj scale to the F maj) according to what scale the current chord uses? So after changing chords to F, rather than using the 3rd note in the D scale(which is F) do we use the 3rd note in F(so we play A)? Or do we stick to the D scale and play the F note again?
I know maybe this is a bit basic and the answer's probably somewhere around the lines of "there are no rules". But if so, I'd like to know the common practice among most musicians. Sorry if i'm a bit unclear.