To add the read more button which appears in the custom module position complete the following
Open up the custom module position you have created
Scroll down to the WYSIWYG editor at the bottom of the module position
Select the tools menu and source code menu in the WYSIWYG editor to open the HTML window
Under the text you have entered into the custom module position copy and paste this text into the HTML window
<p><a class="button" href="#">Read More</a></p>
Change the # to the web site address for the article you want to point the read more button to.
Save the changes
Read more button will now appear in the custom module position you have created