If you're just starting your journey to health and fitness, the first thing to do is just move! The rest will fall into place because you will learn what works for your body. Everyone is different and there are no quick fixes!
"Your are your selfish years. It's a decade to immerse yourself in every single thing possible. Be selfish with your time and all aspects of you. Tinker with shit, travel, explore, love a lot, love a little and never touch the ground.