One neat thing about yoga is that it's an experiential science. This means you don't need to take anybody's word for what yoga is! You get to try it, run your own experiments, and see how it all works for you. You discover what yoga is, based on your own experience. You also get to put it to work for you.
Do you want to let go of stress? Heal an injury? Run faster, get stronger, or just plain feel great? Then practice these things in your yoga! Practice relaxing, even when you're up to something new and unfamiliar. Move easily, everything you've got, in every direction you can. Get to know your body, and practice moving without struggle.
If some part of you doesn't feel good, or feels disconnected, help that part. Practice feeling, and responding to how you feel. Practice moving without struggle.
Make friends with your body, and see what happens from here. You'll be amazed at what you're able to pull off!
Soon enough, stress will be leaving your body and mind, rather than entering and making a home in you. Injuries will heal more rapidly. You'll run faster for longer without tiring, and you'll pull off tremendous feats of strength without even realizing they're supposed to be hard. And through all of it, you'll be easygoing and happy. You're going to inspire yourself. You're going to inspire everyone around you!
Begin at the beginning.
Create your yoga from the ground up, so you're practicing exactly what you want in your life.
Here's a video to get you going with some basic standing poses. If you're new to the practice, you'll build an easygoing and extremely capable practice from the ground up. If you're a long-time practitioner, you can play with these familiar poses, and see what happens as you make things more comfortable and more movable.
Have fun, and let me know how it goes!