The chord progression we are working with in this lesson is C Maj, Gmaj, C Maj, G Maj, C Maj, C7th, which is dominant 7th, F Maj, D7, C Maj, G Maj then back to C Maj. When the song ends, it ends in C Maj.
Also try useing the D dominant7th with the chord progression and without. The dominant 7th is mostly written like D7 exc...
Watch for how many times you strum a chord. Keep in mind that the : d d u u d u is one time of the chord you are strumming. If it's suggested to strum the chord 2 times, then that is only one time. You would have to play that chord again for the second time then go to the next chord and so on. Also watch out for the repeat. It means you go back to the begining and play that progression again before you go to the next set of chords.
When you come up to the chords F Maj. and D7, practice first strumming 2 times on the F maj. then through the progression. Practice again that way through this progression for four times then change to useing the F Maj and D7 for the 1 time through.