Tail Light LED

OH FOR THE LOVE OF GOD can someone please tell me how to hook up my 12v led tailight to my 1976 kz400 D3 without blowing a fuse ? It seems pretty apparent that I need a resistor but I am so horrible with electric it hurts. Any help would be greatly appreciated (and in the most detailed fashion possible) because I literally am so atrocious at this. Much love to everyone here as always I just want to get rid of this thing over my rear wheel.

You should not need a resistor for a taillight. The resistors are used to get LED turn signals to flash at the appropriate rate [when the flasher unit was not replaced with an LED-compatible unit].

Fuses blow because there is a too-high electrical load on that circuit. An LED taillight draws less power than the original incandescent, so - if functioning properly - it should be less likely to blow a fuse.

Does the taillight come on at all? If the fuse is going out as soon as you turn on the key, it is almost certainly wired wrong (or it is defective from the factory). I don't remember the other wire colors offhand but the ground wire [on the bike] will be black with a yellow stripe.

I installed an LED taillight/brake light on a '79 KZ400, so what you are trying to do is not impossible.

You mentioned 12V tail light, not bulb. If you replaced the complete tail light I’d be looking for a pinched wire.

I have replaced all mine with LED recently and found some bulbs won’t fit in the socket. The glass portion will bottom out before the tabs can be engaged. Maybe you have a similar issue and didn’t realize you dislodged the socket somehow and now it’s grounded.

Could be like Nerdy says and the bulb is a factory reject.

I’d try putting all back to original to see if it functions correctly

Probably a short to ground somewhere. A little trick is turning on the lights and observing which light comes on for a second and which doesn't before the fuse blows, The one that doesn't flash indicates the area of the short. Both do nothing indicates a short in the circuit before the 12 volts branches off to the two (four) lights.