It is not stupid. It took me a long time to understand it, too. Then a bit longer to figure out exactly how to do it on my own hair and assess the results.

Some sites say to use shed hair but I've never found that useful and I don't know why. I think they say that so you aren't breaking or harming an intact hair but I just didn't 'get' how to do it that way. I don't know why it would make a difference, but in my brain it did. Maybe that's why it took me so long to figure it out, I don't know.

Anyway, I take a strand (or a few if your hair is fine...just enough so it can be seen fairly easily). With one hand, I hold the strand closer to the root...then grasp the end of the strand with my other hand. I make sure I have at least a few inches between where I am grasping it (I suppose shorter hair would have less to work with). I then pull it straight, then stretch it and release the tension to see how it responds.
remember, with all advice or suggestions for your hair, YMMV!!
My hair:
2b wavy, medium texture, low porosity, med-high density. Protein finicky.
My routine:
Cleansing: DCNP, every 4-5 days (occasionally use CJ cleansers).
RO: CJSC, occasionally use JCDC
LI: KCKT or CJSL
Gel: KCCC, CJCIAB for 2nd day hair (sometimes third)

Heat is my friend: warm water rinses, steam caps, and diffuse dry. I love CLU cloths and my Denman.