On the Instagram app tap “+” at the bottom and choose “POST” from the options, after which take a photo or choose the visual from your phone’s library, follow “Next”, and tap “Next” again in the top right. After these actions follow “Add music”, choose a song from the list or search in the Instagram music library, choose the part of the song you want to add to your post by using the sliding bar at the bottom, tap on the checkmark in the top right or “Done” (for iPhone), and tap “Share” at the bottom.