. Remove and fully charge the battery.

. Test all under hood and under dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

. Check the charging system:

https://www.askmehelpdesk.com/cars-t...ml#post1973613

. Check the ignition switch for wear, pitting, or melting, if the problem persists.

You description infers that you have NO electric power: No dash lights, headlights, stereo, windows, locks, etc. If that's not the case, could you provide further confirmation. If you don't have power accessories like the windows, door locks, sunroof, etc. there's the possibility that you have a bad convenience module or software initialization may have been lost from disconnecting the battery or a power source. Just my .02