can't figure it out - where/when antifreeze

Delaware- -kinda cold, but not too cold

closing up IG concrete pool today, DE filter.

can' t figure out where to put the antifreeze, and when to put it in???

sounds like i should pour some in the 2 returns where the skimmer baskets are/where - do i do this after i blow them out and plug them and after i've drained the pool below the skimmers?

also, should i put in cut up pieces of pool noodle/closed cell foam into the skimmers for space occupying mass?? i read that one of the gurus on here does this.

thank you.