How do I create a members section in wordpress?

A simple way of doing this would be to make your members a registered user of your blog, perhaps at contributor level. Then for content that you only want registered users (members) to see, you could wrap your posts, pages on the following:

<?php if(user_is_logged_in() ) { ?>

<!-- normal loop in here -->

<?php } else { ?>

<p>Sorry but you need to be a registered member in order to see this content.</p>

<?php }  ?>

Take a look here to:

https://penny4them.com/2009/restrict-pages-to-logged-in-users/