Breakdown is a very simple song. I didn't put too much detail. It is quite easy.Enjoy.
The first part is maybe a mix of guitar and whistle.
D G E----------------------------------------------------------| B-----------10~---10-12------------------------------------| G--7-7-9/11-------------11/9-7~---9-7----------------------| D-------------------------------------/7-9~----------------| A----------------------------------------------------------| E----------------------------------------------------------|
A G A E----------------------------------------------------------| B----------------------10--------12-10-----10---10-12------| G---7-9-9b-9-7-9-9b-9b----9r~----------/11------------/11--| D----------------------------------------------------------| A----------------------------------------------------------| E----------------------------------------------------------|
F# G A E----------------------------------------------------------| B-------------------------------------------------10-------| G---9~----7-9-/11-9-9-9-9-7------------7---7/9/11----9-----| D---------------------------9~-----7h9---9-----------------| A----------------------------------------------------------| E----------------------------------------------------------|
D E----------------------------------------------------------| B------7---------------------------------------------------| G---9----7~------------------------------------------------| D----------------------------------------------------------| A----------------------------------------------------------| E----------------------------------------------------------|
D G A E----------------------------------------------------------| B----------------------------------------------------------| G----------------------------------------------------------| D----------------------------------------------------------| A----5-3-5-3-5p3----------------------------------3b-------| E----------------5-4-3-1-3-1-3-3-1-3-1-3-5-3-5~-3----5-----|