when using rockwool, soak the rockwool cubes in PH adjusted water with no nutes for 24 hours, then shake (not squeeze) gently to get the excess water out of them, and soak them in the same solution you will feed your cuttings (so 1/4 strength nutes or whatever you please) for another 24 hours. same again, shake them off gently, do NOT squeeze them, you will change the structure of the voids in the rockwool and possibly create larger gaps for water to sit (less surface area for oxygen, will drown parts of your root system). let them sit for a couple of hours until they stop dripping.
use a stick slightly larger than your cutting stem to form a hole in the top of the cube, pop your cutting in the hole with some rooting gel and secure the sides of the hole in with a toothpick, just push the rockwool towards the stem sightly so it isn't loose. if your hole isn't big enough, do not use the stem of the cutting to push it in, this will damage the cutting. make sure the sides are barely touching so your rooting gel isn't being scraped off as you insert it. if you screw up and the hole is too big to push the sides back in, shred up another cube and gently tuck in a couple of tiny chunks to fill the gap. don't make it too tight.
propagate the cuttings, keeping humidity high by misting the propagator lid, NOT the cutting itself, 3-4 times a day or as needed. if there is condensation on the lid, you are all good. if the lid is clear, mist it up. if any droplets form or drop on the leaves, use a piece of tissue or a Q-tip (cotton bud) to soak them up. if you treat them with great care, they will never fail you. once 2 or more roots have appeared out of the side of the rockwool, you don't need to mist them any more, they will get their moisture from their newly formed root system.
happy growing