This is fairly easy and nothing to it - just buy the store bought apple cider in the juice section - in our commissary near the holidays I've found the cider in the produce section. I just take nutmeg, gloves, and cinnamon and put them in a coffee filter and tie it off really good. Then I take the other end it tie it to the top of the crock pot so it doesn't get lost in the cider and burn at the bottom of the pot.
Depending on how much time you have put it on high or low and once it's hot it's ready to serve - i like to put mine on low for 2 hours before serving - the aroma it gives off while "cooking" is delicious! Be careful this is HOT when you serve it...once you have it "cooked" I would recommend keeping it on warm.
(I forgot to take a picture of when the pot was full so you'll see some of the spice that have seeped out of the bag floating)