The lower dash panel may also need to be removed,(secured with some philps head screws and possibly some 10mm head bolts. Remove the trim panel that surrounds the steering column.(several philips head screws). The instructions in the manual says the battery has to be disconnected and the steering wheel and air bag removed but I don't remember doing that when I have replaced the Civic ignition switch.
The electrical part of the ignition switch is secured to the back of the ignition switch by two small philips screws. There are two anti theft screws that deliberately shear the heads off on assembly when they reach the proper torque to secure the ignition switch to the steering column. These two bolt have standard threads, to remove the "sheer bolts" the head of the bolts are tapped around the outer edge of the remaining bolt head, using a small hammer and small pin point chisel.