Short posts on the homepage

Helo

I have installed ZeeStyle Theme on my blog (ict.2conserve.com). I am wondering how can i turn my each of the homepage posts into excerpts rather than lengthy posts.

I have tried doing that by installing Easy Custom Auto Excerpt plugin but it didn’t work and everything was as before. So, i uninstalled that.

also, upon googling i found the guide (http://www.wpbeginner.com/wp-themes/how-to-display-post-excerpts-in-wordpress-themes/) but i couldn’t find “<?php the_content(); ?>” in the index.php file and therefore didn’t try amending the index.php file.

i am looking forward for your cooperative response.

thank you