I presume you are using the default installed WebLogin system. This means you’ll have a snippet [!WebLogin!] where you want the login form to appear. If you don’t want to use the default login/logout form, you’ll need to specify a chunk to use as a mini-template for WebLogin to use (we call these "tpls" to keep them from getting confused with the main site template). What I always do in cases like that is to create a new chunk, and copy the default tpl (in this case, from the end of the assets/snippets/weblogin/weblogin.inc.php file). Then I edit the chunk until I get the layout I want for my page. As I mentioned, the chunk name has to be the same as the &tpl parameter in the snippet call:
[!WebLogin? &tpl=`FormLogin`!]
Even if you’re using WebLoginPE, the principle is the same as far as the login form tpl goes.
Then you can set up the actual permissions/security for the pages. See
http://bobsguides.com/permissions.html for an excellent discussion on this.