WordPress for membership site created with dreamweaver

Hi, I am brand new so please don’t be upset if this question has been covered a lot.

I have created a webpage with dreamweaver. I want it to be a membership site, where people can sign in and purchase etc. I have no clue what I’m doing with wordpress. None. All the beginner info I have found is discussing making a whole webpage (mostly a blog, which my site is not) from the beginning with wordpress. Could someone direct me to a webpage/forum/book that discusses how to use wordpress in this manner with my current site? Thank you in advance. ??