Remember that downward dog focuses more on elongating the spine and keeping the back straight. Slightly bend the knees if needed to achieve this, you'll still get a hamstring stretch. Also note that your knees and thighs aren't touching the ground for the upwards dog and is active throughout your entire body, not just your upper body. Match your breath with the flow.

I could not find a video to match exactly how I was taught. My instructions are to also crawl your same side hand forward just as far as that knee if forward (left knee forward, left hand forward, both about 5-6 inches) On the same knee that is forward, you have that foot flexed (bent) and the opposite foot extended (Flat)

I recommend reaching up with one arm in both directions while in the stretch for a spinal twist each way.

Explore the stretch by moving your bent knee higher for more glute stretch, lower towards the ground for more twist in your back, etc. Connect with your breath and melt all of your muscles into the ground.

Grab a towel, lay it over your face and enjoy a nice 30 minute massage in the chair at the gym.