Where do i create citizen wagon? and what does it do?

i couldnt create citizen wagon, i clicked on urban center and i didnt find how to create them

Only the Germans can build Citizen Wagons. You must also send the Germantown Farmers card that allows you to train settler wagons in mills, you don’t send this card, you can’t train them.
After you revolt and get citizenship, they turn into “Citizen Wagons” and can be trained from mills again(but only if you got the card before revolting).

oh ok, i wa splaying brits and i only could create vilalgers even in mills. ok then i cant