http://www.GuitarLessonGuy.com/twochordsong.html –TAB & GP5 files can be downloaded here.
EX 1 Starts at 5:15
EX 2 Starts at 6:25
EX 3 Starts at 8:35 (full play-along starts at 11:30)
EX 4 is the same as EX 3 but you can play just the base note on Em