Hi Tizis,
To insert the ellipsis, you can open up the content.php file in themes/dw-minion folder, and find the code below (around line 10):
<?php the_content( __( '<span class="btn btn-small">Continue reading</span>', 'dw-minion' ) ); ?>
.. change it into this:
<?php the_content( __( '<span class="more-text">...</span><div class="btn-more"><span class="btn btn-small">Continue reading</span></div>', 'dw-minion' ) ); ?>
After that, go to Dashboard / Appearance / Customize / Custom Code, and add the following code to Header Code section:
<style>
.more-link {display:inline;}
.more-text {display:inline-block;cursor: default;}
.more-link:hover .more-text {color:#666;text-decoration:none;}
.btn-more {display: block;margin-top: 20px;width: auto;}
</style>
Hope that helps!