I am very rusty but had an E46 with xenons and often took it abroad
Theres a lever which you've found, good effort by the way as its not easy, and the configuration of which one to have up/down or whatever is in the manual - sorry I cant remember
The lever just cuts off the sided 'kick up' that would otherwise blind oncoming drivers, I think to have a left hand one you'd need a proper RHD headlight