GUITARISTS!! HELP!!!?

There's only 12 notes in the major scale. A, A#/Bb, B, C, C#/Db, D, D#/Eb, E, F, F#Gb, G, G#/Ab, then back to A (the next octave.) Half steps are the next note in order, full steps are two above or below. To change a key of a song just travel the same amount of steps down or up the scale the scale as needed. To drop a song from F to D# (that's a full step lower) slide all the notes down 2 notes. F=D#, G=F, C=Bb, E=D.