On a 97 Civic (most models), the keyless entry unit is the factory radio. You press the little slim button (I know it doesn't look like one, that's the point) between the two buttons all the way on the right. I don't remember exactly which buttons they are, but tonight I will take pictures if I get a chance. You hold that slim button in and press the "lock" button on your remote. The locks on your car should cycle, and you know you've got it. Repeat it for every remote you want to program.