To play Queen's Crazy Little Thing Called Love, we'll need the following chords:
D major, which we'll often augment with a G (Dsus4) using the little finger on the high E string.
Then we'll need a C major,
and B flat major.
For the bridge, we'll need an A major and E major.
At the end of the bridge there's a little bass riff which uses the following notes: D, D-flat, C...A, A flat, G...and finally; E G flat, A flat, A, G, G flat, E.
Here's a slowed-down version of the chord sequence.
And here it is at the original tempo.