cloning?

cant you just put your root cuttings dipped in root hormone right into potting soil without all this fancy rockwol stuff.. can it be done this way?

Yes it can be done that way.

Make sure your soil is muddy wet to very wet (if using potting soil). An easier way is to use rapid rooter plugs or pellets. Here is a good explanation with pics.
https://www.rollitup.org/subcools-old-school-organics/50073-cloning-subcool-redundant-explanation-pictures.html