Either plants grow through it naturally and it provides support while also slightly separating colas in a systematic fashion, or you can use them to LST the plants by tying it down to the scrog as it grows or just keeping it under the net as it grows, then let it go vertically. both functions work well.
it shouldn't really get in the way of anything in either of these case unless you tried to put a scrog down on top of already fairly large plants. Better to let it grow into it. HAve the scrog up before the plants get there.
fit things through the mesh before it gets too big. New growth is pliable so fitting things through should be easy. Work any fan leaves through then slip the terminal through or whatever... bend and shape the limb as needed to spread the plant out.
if going to flower soon it won't matter much for you. Just keep spreading the plants out as best you can - bend the limbs daily or use garden ties. If it need support with fat heavy colas (some plants do), you'll have to tie individual colas to ceiling or something to support them without a trellis or scrog. Don't let them flop over. Anythign that droops downward will get less resources (apical dominance or lack of in this case) This type of stuff often rests on other foliage or walls, which is just a disease waiting to happen.
As one who avoided scrogs and trellis nets, learn to use one. It is beneficial. You never know for sure when you will get a floppy plant that cannot hold its own weight. tying up a ton of colas for support is a pita that is completely avoided with a trellis or scrog.
i use one level of scrog with the nicer/more robust stretchy parachute cord material, but my 2nd level is just for supoprt, so i use a cheap as i can find trellis net. I use the scrog to train it out before going vertically.
If instead i just let it grow through to slightly spread out a plant, i would only use 1 layer of net. A cheap trellis will keep everything upright and positioned a bit higher on plants for best support.