Add a directory within my own theme and not in front page

I want to have a directory page (ie not the front page) and I want to use my own WP theme.
('cause you know I won't build that a second time by tweaking your theme).

Is that possible ?
(I didn't really found a clear answer in the forum)
No way for me —like it was suggested elsewhere in the forum— to do that with an other WP install.
I just want to integrate a directory in a special page inside my actual WP install.