The sidelights on the e90's are:
Jack up the car
Remove the wheel
Remove the mudguard
Crawl under the car
Remove the cover (this is fiddly and requires 2 screwdrivers and hope)
Unbolt the light (this requires 2 torx heads)
Reverse to install
Not too bad if you have access to a ramp, but with just a jack its bad back city
Tbh the bmw manufacturers mentality is you pay the service package and they do this on a yearly basis so you should never have a blown bulb. Its funny that they combine that level of complexity for a blown bulb with an oil sensor that tells you when to add oil and how much to add.
It's madness, on the F30 the sidelights require no tools, I changed a blown bulb on mine about 4 weeks ago in Halfords car park!