Hi Readthebook and welcome to the forum.
I do gentle yoga twice a day. It makes me feel so much better. I walk the dog first thing in the morning and then do about
30 minutes of yoga. Then in the afternoon I do about
20 minutes of some different stretches after using the elliptical machine.
I was taught yoga by a trainer and I am very careful not to over do any of the poses. I am sure you could go on line and find some gentle yoga instructions. I actually have a great dvd that I bought from Kripalu Yoga online. It's called Gentle Yoga. I don't know if they still sell it though.
Good luck!