It would be essentially the same as connecting a battery in the car, except with longer cables. You would have to use jumper cables to extend the car battery cables.
Be sure to follow ALL safety procedures. Do NOT let anyone or anything metal touch anything else except where you make the connections. Do not touch the metal connectors themselves.
I assume there is no battery in the car. I will call the battery that is not in the car the "external battery".
First connect the positive ("+", usually red) jumper cable to the positive car battery cable, & then the other end of that jumper cable to the positive external battery terminal.
Then do the same with the negative ("-", usually black) car battery cable & jumper cable. The last thing you connect should be the far end of the negative jumper cable to the negative terminal of the external battery.
When you are ready to disconnect the external battery from these cables, do so in reverse order, starting with disconnecting the negative ("-", usually black) jumper cable from the negative external battery terminal.
Disconnect the negative cable first when disconnecting a car battery
Connect the negative cable first.
Disconnect the negative cable first when disconnecting a car battery
Connect the Positive + battery cable to the positive + battery post first. Then connect the Negative - cable to the negative - battery post.
Disconnect negative cable first from old battery and connect it last when installing new battery.
red or positive
Connect the positive + red charger cable to the positive + red battery post. Then connect the negative - black charger cable to the engine somewhere. Most engines have something metal sticking up that you can connect to. Do not connect the negative charge cable to the negative battery post, always connect it to the engine.
Remove - battery cable Remove + battery cable from battery and starter solenoid Route new cable following original routing Connect to starter solenoid Connect to + battery terminal Connect - battery cable
Connect the red cable to the dead battery's positive post and then connect the other end of the red cable to the good battery's postive post. Then connect one end of the black cable to the negative post of the good battery and the other end to a piece of unpainted metal in the engine compartment of the dead battery's car. Then wait 2-3 minutes and try to start the car.
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.
The plus is Positive + and it connects to the Red cable which connects to the starter.
Always disconnect the negative cable first. When reconnecting always connect the positive cable first.