One basic point, you have to “build” the length of the extender when starting out.
One cannot build up tension by pulling on something that is stretching out as it is being pulled.
Lets say you can stretch your 3” flacid penis to 4”.
You will need to construct the rods in your extender so that it is approximately 4”. Now there is some variancein the 4”, as to where you fasten in at, and a given that you will compress the extender, fasten in to the cradle, then release so the springs take over.
It helps to warm the penis, do some has jelqing, stretching first before fastening in.
So you fasten in, and generally, after 20 to 30 minutes, you penis will relax/stretch out some more, the observed tension lines will show less than you fastened in at. Normal.
What you are tasked to do is decide what tension to adjust to at this point in time. Study this over a few months, and see what best works for you.
There is the tension you mount in at, mounting tension, and half hour later, the tension you are wearing at, wearing tension.
If you use these terms in your posts, it will be more helpful in collecting advice.