- connect the red connecting wire to the positive «+» terminals of both batteries;
- connect one end of the black or green jumper wire to the negative «-» output of an additional battery;
- connect the other end of the black or green jumper wire to «mass» car parts located as far as possible from its battery;
- turn on the starter and start the engine;
- wait for the engine to idle steadily and remove the connecting wires.