disconnect the negative (black) first then positive (red).
No.
Hook positive up first, negative last.
No, you can charge it in the car fully connected.
Why do you want to unhook your battery??? If the alternator is good the car will continue to run, if it dies then you have a bad alternator this is why you would want to unhook the battery cable to check and see if you have a bad alternator
Unhook the car battery.
You probably have a failing alternator.
Always hook red up first, black last. Unhook black first, red last.
Hook up the positive first and the negative last. Unhook negatives first when removing.
You can either pull the fuse or unhook the car battery.
Just hook up the charger to the battery while it is still in the car and do not unhook it.
With a scan tool, or unhook the battery for five minutes.
You just unhook it remove and put the new one in.