php - how do I edit my wordpress site navigation -

I have noticed that website site navigation is a cool side indicator next to each link I want to add something similar to my website , But I do not know which file I want to change.

I am currently using a wordpress theme called Square and I currently have an effect. I want to work on a link which is the Home URL link, which by adding a class called 'Indicator' The functions.php file inside the theme is edited, but it does not appear to be visible to any other, resulting in the menu being displayed

  / ***** **************************************************************************************************** ******************* ************ Main Menu Fallback ************************************************************************ **************************************************************************************************** *********************** / Function Menu_Followback () {if (is_front_page ()) {$ class = "current_page_item"; }? & Gt; & Lt; Div id = "dropdown" category = "clear menu" & gt; & Lt; Ul id = "menu-main-nav" class = "sf-menu" & gt; & Lt; Li class = "& lt ;? php echo $ class ;; & gt; & Gt; & Lt; A href = "& lt ;? php echo home_url () ;? & gt;" & Gt; & Lt ;? Php if (get_option ('square_home_menu')! = "") {Echo get_option ('square_home_menu'); } And {_e ('home', 'class_long'); }? & Gt; & Lt; Div class = "pointer" & gt; & Lt; / Div & gt; & Lt; / A & gt; & Lt; / Li & gt; & Lt ;? Php wp_list_pages ('title_li = & type_column = menu_order'); ? & Gt; & Lt; / Ul & gt; & Lt; / Div & gt; & Lt ;? Php}   
 I was thinking that there is something that I can add to this PHP string so that it can add all other links added to the menu or add an index to another WP structure In the file should I edit it to work?  
 Please note that I am a PHP noob   
 
 
 because there is no meaning in the dots Not worth the price, I would go for a CSS solution.  
 
 Alternatively you can use background images.    / html>