Cloverfriend shared some great chords for Smile. They work well for the guitar—or for ukulele, which is how I tried them out. The chords Cloverfriend wrote give a nice simple progression that is easy for beginners (like me!) to play. Very well done, Cloverfriend! If you want to play along, you can find the chords here.
(Side note: this picture is my favorite moment in the Smile song. It practically makes me tear up when I see it. Friendship forever!)