green and black , as your looking at it its the furthest left.
Connect positive first and negative last.Connect positive first and negative last.
Yes connect the positive first to the positive battery post, and then connect the negative ground to the engine somewhere and not to the battery.
Take off the cover from the back using a Phillips screwdriver. The taillight assembly is bolted on to the body with 3 #10 bolts that you can now see. Take those out. Then you will have a simple electrical quick connect that you will have to disconnect. Pretty simple.
Sounds like you are reversing the cables.
There is positive and negative. The positive energy can't connect to a another positive there's a force between them that's doesn't let them connect. Same with negative energy it has to connect to positive not negative.
Yes, you always connect positive first.
The battery post positive terminal is where you connect the positive cable. Connect the negative cable to anyplace on the engine or chassis. Connect positive first and remove it last.
Reversing the cables when you connect them. Overcharging the battery.
You don't, you connect to the battery from the battery of another car. Use the positive cable to connect the two positive electrodes and the negative to connect the two negative electrodes.
Always connect the positive first.
The positive
Connect positive first, negative last.