How to edit the code to show categroried as wish?

Sorry that our previous solution was a bit confusing and not really helpful.

Please find my new solution here:

Step 1 Open wp-content/themes/dw-argo/index.php file with a Code editor (Sublime text 2 or Notepad++)

Step 2 Find those codes (See screenshot: http://i.imgur.com/pqMP9Zt.jpg):

<?php if ( have_posts() ) : ?>
    <?php while ( have_posts() ) : the_post(); ?>
        <?php get_template_part( 'content', get_post_format() ); ?>
    <?php endwhile; ?>
    <?php dw_paging_nav(); ?>
<?php else : ?>
    <?php get_template_part( 'content', 'none' ); ?>
<?php endif; ?>

Then change to (See screenshot: http://i.imgur.com/oNgVqhd.jpg):

<?php $wp_query = new WP_Query('post_type=post&category_name=coding');?>
<?php if ( $wp_query->have_posts() ) : ?>
    <?php while ( $wp_query->have_posts() ) : $wp_query->the_post(); ?>
        <?php get_template_part( 'content', get_post_format() ); ?>
    <?php endwhile; ?>
    <?php dw_paging_nav(); ?>
<?php else : ?>
    <?php get_template_part( 'content', 'none' ); ?>
<?php endif; ?>
<?php wp_reset_postdata(); ?>

Note: Remember to change category_name=coding with your category as you want to display to the homepage.

You can find categories name by go to Dashboard > Posts > Categories. Then see the column Slug. See screenshot: http://i.imgur.com/xEu5NbI.jpg

Another thing, to use multiple categories, you just add more slug like: category_name=coding, wordpress, design

Hope this helps,
Jackie