From the link: > Once inside your vehicle, insert your remote key fob in the ignition slot or, if your car doesn't have one, hold it against the key markings on the side of the steering column. You'll then be able to start your BMW with the start/stop button on your vehicle's dashboard, even if your key fob is dead.

Other cars probably have other solution. It was possible in my case as well (not BMW) but do not remember the process.