HELP I Screwed UP...I Think?

[crzo68]

1) well i got the horn contact kit from chevytruckandcarshop.com as well as other parts... so i put the horn contact kit installed to best of my knowledge but then the horns Worked bUT wont shut off_ so i unplugged horns and but i didn't touch steering wheel so i think the horn was still going off... 2) so i then decide to put on my safety neutral switch...wrong part so put old one back on but lost 1 screw. and after all this the horn ,s.n switch ...the 1972 GMC is dead-... i charged battery ,nothing...then tried to jump start it which then melted my jumping cables but no lights no power nothing ...what did i fry? i thought the horn contact or S N switch etc...but battery started to boil a bit i think....any ideas the truck was perfectly fine until this morning???