To echo Jimbo's words, it couldn't possibly be any easier unless someone calls you up and then arranges a car to collect you from your apartment/hotel and bring you out. Most of the nights out are organised directly on this forum in clear simple words. Look at the first page of the Forum, click on the
Events - Toytown Meetups link, look at everything that's arranged and jsut go along to one that takes your fancy. If that doesn't work then click on the
Going out - Munich Nightlife link (it's directly above the other one) and have a look for something you like in there. Failing all that then pick somewhere to go and/or something to do yourself and just set a date and a time. If you book them they will come. It really couldn't be simpler. Anyone who signs up for this forum and then says that they cannot meet people for a night out in Munich due to not knowing anyone or any of the places is either blind and waiting for Ed Bob to introduce a braille version or is seriously lacking in the cop-on department.
So just get on with it, get yourself out and have a good time. On the whole you will meet a great bunch of people. I can almost guarantee it.