There a certain set of dash lights that should light up and blink/glow steady when you put the ignition into RUN (without starting/before starting). If those do not behave as expected, or if this blinking security light is the only response when putting ignition into RUN (before starting), then yes, you broke something that will need to be fixed.
Whether that 'something' is a fuse, several different fuses, a relay, a fusible link, etc. is something you will need to determine before you can move forward obviously. Start from scratch - unhook both battery cables and leave them unhooked for 15 minutes. While they're unhooked, test battery voltage. If it's good, then hook cables back up and turn ignition to RUN. Observe dash lights. Do they behave as expected, or is it still off-nominal? Proceed accordingly...
If you can get your hands on a Haynes/Chilton's manual for that vehicle, it will probably help you diagnose any electrical/ignition issues you might be chasing.