Just paste this text in Function.php file
//Read More Button For Excerpt
function themprefix_excerpt_read_more_link($output) {
global $post;
return $output . ' <a href="' . get_permalink($post->ID) . '" class="more-link" title="Read More">Read More</a>';
}
add_filter( 'the_excerpt', 'themprefix_excerpt_read_more_link' );
second step is to use the_excerpt() insted of the_content();
