So I recently bought iflight nazgul5 v2, flysky i6-x radio transmitter, the connection on the drone didn’t have the wire to connect with flysky reciever, so I found that you just can connect them with special wires to special wires, the reciever light up perfectly, but I still didn’t have a battery, i just connected the drone to computer, to bind my drone, i needed a binding pin, which i lost somewhere, so i figured out i could use it like binding pin, first times it worked perfectly, the drone connected, on the radio you could see it shows the reciever battery etc, but it couldn’t arm/disarm, because the betaflight couldn’t find the radio that means something is bad, until yesterday i was dumb, so dumb and i tried it again, this time it did nothing just the drone wire which i was connecting with my pc, my pc restarted, i though its ok, i tried again, but then this time i believed wire touched another part which it shouldn’t (in the reciever), then the esc? i believe, maybe flight controller started burning (smoke started to go from one part), i immediately took it off, opened window and just placed it so it would cold off, today i tried connecting the drone, and the part which burned, still light up, the light was red, i don’t know what this means, can anyone explain?
Sounds like you may want to start at the beginning and reflash firmware as a solid red light means the FC is not booting up, so perhaps just reflahsing firmware will help.
Once that is done you may want to try going through this basic setup guide How To Setup Any Betaflight 
Flight Controller (dronetrest.com)
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