You'll have to use a modelling program to reshape them, first. Poser cannot do that. Then you will need to learn how to either hack a CR2 (about six hours) or purchase the Clothing Convertor to do the rest. This isn't an easily done thing, and requires considerable knowledge of how poser works if you go the hacking a cr2 route. That said, at the top of the page, beneath the advertiseent, is a set of links -- one of them is tutorials. One of the options there is for offsite tutorials. Go there, and start reading. This is a subject pretty much beyond the ability of a single post to teach you simply. If you can narrow the question down specifically to fine points, that will help a great deal, and is more likely to get you good answers.

thou and I, my friend, can, in the most flunkey world, make, each of us, one non-flunkey, one hero, if we like: that will be two heroes to begin with. (Carlyle)