Please share a tip on some do's and don'ts with regard to yoga.

Drink. Drink plenty of water when you are doing "hot yoga." take breaks and lie down if you feel dizzy.
Learn. Learn from a well qualified instructor and do not rush your progress.
Everyone. Everyone with chronic low back pain should seek some basic instruction. It really helps.
Do. Do go slow with yoga postures. Don't brutalize your body with difficult postures learned the fast way!
Don't. Don't overdo it on your first yoga session. In time you will be able to do all the poses.
Do. Do go to a yoga class for proper instruction. I don't advise self- taught video yoga: inc injury.
Do. Do not stretch beyond your comfort. Build your flexibility over time.