You should watch the lesson and learn the D7 chord so you can play along with the song. You can begin by using one strum for each chord and then progress onto playing 4 strums per chord.

 

You need to watch both links:

https://wakefieldgreenhill.primarysite.media/media/im-yours-jason-mraz

 

https://www.youtube.com/watch?v=BFxVN_wVBgs&ab_channel=DrJillReese