97 Chevy pick-up

You have to make sure the battery has a full charge and all connections are good. If you turn on the headlites and turn the key to crank, any reaction from the lites. If they go out or almost, usually the battery or cables. They stay bright, no reaction, look for an open circuit to the starter. Possibilities, ignition switch--wiring circuit-- neutral or clutch switch depending on if you have a manual or automatic tranny. Starter itself could be an issue? Any testing, make sure the tranny is in park or neutral and the e-brake is set. Block the wheels if needed.