If you want to show only 5 posts you should set posts_per_page
to 5.
And by setting paged
parameter to any number you want, you can query posts in a specific page.
For example if you want to get posts 6 to 10 you should do:
$args = array(
'post_type' => 'project',
'posts_per_page' => 5,
'paged' => 2
);