In general try these things
1 for something like removing a wheel, always consider your owners manual. It should be accurate for your exact model/yr. It will also explain use of the jack and the jacking points.
2 find and bookmark at least four forums, bimmerforums,e46fanatics,bmwcca(join the club) and get used to using them
3 try this diy link, lots of places have diy sections, google bmw diy,
this link is on changing e39 pads actually this is the home page just choose last one under maitenence, changing brake pads, it has pictures and blow by blow
there is no reason to ever reinvent the wheel on these cars today in the day of the web, its all been done and documented BMW E39 DIY (Do It Yourself)
there is no center lugnut, I'm not sure to what you are refering
Best of luck