Start with Dan's suggestion and get more familiar with terms, data needs etc when using NA. Your question is quite broad; perhaps you should consider a few things like: existing bus routes, existing stops along those routes, any admininistrative requirements for stop locations (for example, minimum distance between stops) etc etc.
Also, take a look at this discussion from a couple of days ago, paying close attention to cdspatial caution comments.
Good luck in your adventure!
Dan_Patterson
That should just about do it....