Watch the After You’ve Gone online guitar lesson by Brooks Robertson from Essentials: Boom-Chick Fingerstyle Etudes
First take a few moments to watch and listen to the performance video. This will help you become more familiar with the tune, form, phrasing, etc. Remember as you watch, focus your attention to what the right hand is doing, then rewind and watch again, this time focusing on what's happening with the left hand. Note how often the thumb on the left (fretting) hand is used to play over the top of the neck, fretting a bass note. Use this video as a resource to frequently reference and eventually to play along with as well. Don't forget to utilize the tabs, charts, and notation.