looks like it was stolen and sounds like a scrap-er... it would probably be easier to buy one in better condition than trying to restore your current one... but if ur really deadset on fixing those...
first, start by either downloading a factory service manual (theres troubleshooting pages regarding your idle situation), in ur case itll probably be better to go out and buy the hardcopy because ur gonna need it,
check ur grounds, that could be causing the blown fuses,
reconnect all the wires and see what happens,
i just noticed the shit-ton of rust... check ur frame... u really might wanna get rid of it if ur frame is rusty, i had an s13 like this and the frame actually caved in while i was driving it
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u most likely have a vacuum leak causing ur idle problem,
other possibilities are: sticky EGR valve, injectors and circuits, spark plugs, fuel pressure, heated oxygen sensor, idle-adjust screw clogging, and compression... sounds like a lot but its easy stuff to check,
your horn and seatbelts are probably disconnected somewhere,
all the stuff that doesnt turn on until u rev it probably have dirty/bad connections,
keep me updated on those issues, im interested to see how this turns out