Can't show post summary on wordpress.

you might have either edited the wrong file(s) or your site is cached…

what theme are you working with?
what files have you edited?

unless you have set a static front page (https://codex.wordpress.org/Creating_a_Static_Front_Page ), the home page would be the index page which is usually done via index.php or home.php

Hi
In your themes functions.php file write the following code :

function new_excerpt_more( $more ) {
 return '... <a href="'.get_the_permalink().'" class="more-link">Reads More »</a>';
}
add_filter('excerpt_more', 'new_excerpt_more');

This filter works with the_excerpt();