When is your first bill and auto pay due after installations?

We have a scheduled appointment tomorrow for new internet, land line and cable. When I signed up it defaulted to Auto - Pay.  I know they bill a month ahead, but if my installation is tomorrow on the 4th when is my bill due?  and is that the same auto pay date or is that earlier or later?   Never done  auto pay. (it needs to be a pay week date for us). I am hoping they don't expect the first month to be paid on the first day of installation with the auto pay set up.