The instructions said to use a straw as a filler hole and to drill a overflow hole in the bottom third of the water reservoir, but I didn't have any straws so I just made a hole that can serve as a filler hole and an overflow hole.
I know it's a little hard to see, but it's a half-moon shaped hole just about where the bottom of the label was.
The second one has a wick made from two paper towels. One towel is folded in half, and folded again. Then it's folded in half the other way and rolled into a tube. The tube is then set in the center of the second paper towel and pushed about halfway through the mouth of the bottle. The long tail of the second paper towel is spread out to catch the soil when it is added.
I have some reservations about how long the paper towels will last. I've seen some involving sponges and old tee shirts. Might give that a try later.
Here's a video of how to do this one
All of the tops were inverted and pushed down into the ends of the other section of the bottle.
Then I put soil in the containers and watered it from the top to get everything working. The one with holes just gushed water and the overflow hole did its job. The one with the paper wick slowly trickled down and the water is amazingly clean. The yarn wick one took the longest to flow down. The soil is still a bit soupy.