Menu icons not visible

Hi there

I’m working on a site using the Custom Community template and was trying to make the theme’s main menu show some icons using the Menu Icons plugin, unfortunately the icons are not visible, the plugin help states something like this:‘Make sure that your active theme is using the default walker for displaying the nav menu. If it’s using its own custom walker, make sure that the menu item titles are filterable (please consult your theme author about this).’
Could you please help with this, i googled it but it gets wayyyy to technical…