Learning familiar tunes is a great way to get started. I have heard great teachers claim “If you can’t say it, you can’t play it”. Meaning if you don’t know the melody or the rhythm pattern to the music you are trying to learn, the best advice may be to listen over and over until you can hum or sing along. Music is a language and just like when you learned to speak, first you imitated sounds that you heard from others. Over time you learned words, phrases, and eventually could speak in sentences and even complete thoughts. At that point you were introduced to the printed word. Unless you are already a good sight-reader, the sheet music/tab may not yield the results on it’s own so don't rely too much on it. Listen and imitate.