The four in the first measure indicates the four measures of rest during the piano introduction. I put the guitar chords above the bass part, but here they are typed out too:
|: A major / C# minor / A dominant 7 / D major
F major / E major / D major / A major :|
B major / D minor / A major
B major / D minor / D major / E major
|: A major / C# minor / A dominant 7 / D major
F major / E major / D major / A major :|
~key change~
|: Bb major / D minor / Bb dominant 7 / Eb major
Gb major / F major / Eb major / Bb major :|
C major / Eb minor / Bb major
C major / Eb minor / Eb major / F major
|: Bb major / D minor / Bb dominant 7 / Eb major
Gb major / F major / Eb major / Bb major :|
