Yoga at Home

I've read many positive comments about yoga improving the quality of life for arthritis sufferers. I've never read much on what yoga involves, but I am curious. I Googled to find out what is available in yoga that can be done at home. From the pictures of the poses Mr. Yee assumes, one thought comes to mind: OUCH! I don't think my body can bend like that. Scanning the article, I only need a few props, one of which is the yoga mat, AKA a sticky mat. I see it is necessary to prevent slipping when I start to "sweat". Do I have to sweat? And just what is an upward-facing dog? Scanning further I see that a full page is dedicated to teach me how to fold my blanket. Guess if nothing else, I can learn a new way to fold the covers. Guess the pressure is on to see if I do more than scan the article and fold blankets.