Patience ... Which are you looking at, horizontal or vertical?
I switched to the horizontal ... Stick your finger under the silver lever until the water drips out into the "cup". They'll get curious & check it out. If you can get one going the rest will copy. Some say to remove the regular waterer, some prefer not to.
Main thing is to monitor, you could remove in the mornings & for peace of mind put the regular on in at night?
I only have 4BO so I use a hard plastic gallon container, drilled a small hole about an inch below the rim, recommended 1 nipple/4 chickens (I installed 2), I mark the level of the water (monitor), test the nipples every time I change out water. For some reason when I change the water they are waiting for me to "test" the nipples & drink what comes out. I know they're drinking on their own as the water level goes down.
New to chickens myself. We use buckets with the nipple fill cups for some and bottle waterers like you would use for rabbits on the small chicks up to 8 weeks old. It's like, monkey see monkey do. If one figures it out, they all do.
I'm guessing your gonna use horizontal nipples, vertical nipples will freeze. I don't know what your thinking of using for a heater, but I recommend a 250 watt stock tank deicer. Just put the waterer out there, with the nipples at back height. Tap the rod a few times with them watching. After one or two use it they will all start using it. Below are pics of what I did to run the deicer cord through the lid, using a computer grommet and rubber grommet, that I got at Lowes. Drill a two inch hole for the computer grommet(it's 2 pcs) to go into, slice the rubber grommet so it will go around the cord.
I can’t seem to get mine to use my horizontal nipples. They are interested when I push the water out and will drink the drops that collect but then they peck at red part but not the silver then walk away because water doesn’t come out. I even tried a red laser pointer thinking my finger was in the way but nope. Three weeks they just can’t figure it out.
Go to the gas station and get a $1.00 laser pointer. I shined mine in my horizontal feeder for about 2 seconds and they were chasing it like crazy, pecking and quickly realized there was water in there.
You don't teach them. They are attracted to the color red and the shiny silver thing. They will peck at it to see what it is. As soon as one gets water, within an hour they all have learned. The key is to remove all the other water sources. If you do not do that they will not learn. The neighbors on either side of me also had free ranging chickens. Even those chickens learned to use the nipples rather than go home for a drink.