Posts per page with pagination

I had code for my blog page in WordPress but it shows only 6 posts and ignore the rest so pagination doesn’t work (shows just 1 page). I know that it works fine with this code but I can’t change it for my requirements.

<?php get_header(); ?>

<div class="container clearfix">
    <div id="content" class="clearfix">
        <?php
                $postslist = get_posts('numberposts=6&order=DESC&orderby=date');
                foreach ($postslist as $post) :
                        setup_postdata($post);
        ?>
        <div class="entry">
                <div class="recent-post-thumbnail">
                        <?php echo the_post_thumbnail($recent->ID, 'thumbnail'); ?>
                </div>
                <h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
                <?php the_excerpt(); ?>
                <h4><a href="<?php the_permalink(); ?>">More ></a></h4>
        </div>
        <?php endforeach; ?>
  </div> <!-- end content -->
  <div class="vertical"></div>
  <div class="sidebar">
        <?php get_sidebar(); ?>
  </div>
</div>
<?php wp_pagenavi(); ?>

<?php get_footer(); ?>