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Do you have a voltmeter and a reasonable knowledge of how to use it?
In order to figure out what's going on we need to check for voltages at specific points in the system, can you get at least a simple 12 V test light from a nearby parts store? About 90% of the time the only thing it gets damaged when jumping a car backwards is the fuses and the main ALT fuse that supplies power to the entire fuse block system under the hood. This is a modular fuse block link assembly. It's difficult to see the fuses in there but they're probably blown. Will you be able to get a simple 12 V test light or are you just looking for general ideas as to what could be going on so that you can car towed somewhere and have it inspected and you can be informed as to what your options are.
The ALT fuses built into the fusible link block. Click this link and download the pictures. It will give you a general idea of what has to happen in order to get to this fusible link block and/or replace it. Using your 12 V test light connect to the negative battery terminal and back probe the fuses in the fuse block on the hood to have 12 V any them with the key on? There is also a large cable with a 10 or 12 mm not holding the cable to the main fuse block do you have 12 V to that post? The bot***** *****ne is in order to replace that fuse block it has to be disassembled as you seen from the pictures I posted. That is not a job for someone who does not have a lot of technical ability and lots of patience. Your fuse block may not be exactly the same as this one but it will give you a general idea of what you will be dealing with.