Carrying out:

WARNING: This page is about a different car, the 2002 BMW M Roadster, 2002 BMW M Coupe, 2001 BMW M Roadster, and 2001 BMW M Coupe. However, it is still accessible from the selected car via links, so may be relevant.

Always conform with the procedures to avoid injury to persons or damage to parts.

On automatic transmission, select "P" setting, apply handbrake.
Move the shift lever of vehicles with manual transmission into neutral and apply the parking brake.
Ensure that the jump leads cannot get caught in rotating parts, e.g. fan.
First connect positive terminals of both batteries with one jump lead (red).
Use positive connection point in engine compartment for vehicles with one battery in trunk.
Then attach second jump lead (black) to negative terminal of donor battery and to engine ground or body ground on vehicle to be started.

CAUTION: Never connect second jump lead (black) to negative terminal of battery in vehicle to be started. This would produce explosive gas which could be ignited by sparks.