Haynes manuals range from barely acceptable to completely useless, depending
on which vehicle you have.  Some Chilton's are better, and some are not.
The be-all end-all is a Honda factory service manual, but you have saved
some money buying the Haynes.

If you look under the hood you should be able to trace the two heater hoses.
You can feel them and see if hot coolant is being pumped to the heater core
and back.  Do this with the heat control turned to maximum heat and the
engine of course warmed up and running.  On my 1999 Civic there is a
cable-controlled valve that opens and closes this circuit.  You can see the
valve opening and closing as you turn the heat control knob.  A possibility
here is an air lock in the system.  Do you have reason to believe that
coolant level is low, or has been low recently?  Follow the Owner's Manual
instructions for topping off the coolant.  If you are getting hot coolant to
the heater, and still no heat, then the problem is in the air control
mechanism.  When you say you get no heat, do you mean no air is flowing when
the heater is turned on, or that you are getting plenty of air, but it is
not hot?

Earle