Once you leave them out to dry by hanging them you need to bring the moisture out from the inside of the bud so you don't risk mold
So putting in a bag will bring all that moisture back out from the inside and it will feel wet again then you dry them again in a net or just leave out on a tray to dry
Then once it feels dry again you put it in to jars to start the cure but opening once a day for a few days will help make sure the buds are dry and won't mold if you don't let it dry right it will get moldy
Plastic bag or paper bag work fine just close the end to make it sweat