1963 Other Chevrolet Models 63 chevy pickup - no electric?

Hi,
i just got a 63 chevy c-10 pickup, the wiring is a mess.
the headlights stopped working, everything else was ok. So i checked the fuses, one was blown, while replacing it i noticed a spark.
Now nothing works, lost all electricity, no lights, no ignition, just dead.
Checked battery terminals and battery charge, both are good.
Any suggestions of where to start?

Im going to do a full wiring harnnes eventually but im not ready yet.

thanks
Chris