I have seen these, I have them! This style of band is more for assisting you in deadlift style moves. With it being so thick and heavy it’s not meant for strength work but holding body weight. So you’d put it around a thigh and work on Iron X or lifts, as one example. If you bought the set you can use the thinner (red I think is the color) for strength work. But the really thick ones are to hold body weight.
These are great for strength work and I use a similar set in the strength and conditioning lessonshttps://www.amazon.com/QDH-Resistance-Exercise-Stackable-Workouts/dp/B08CGM6S9J/ref=sr_1_76?crid=1G3C6RA01HT70&dchild=1&keywords=resistance+bands&qid=1608574512&sprefix=resis%2Caps%2C216&sr=8-76
Here’s a video I made for you. https://www.studioveena.com/videos/view/5fe0ee76-6948-400b-bab0-7be6ac110005