Releted products layout

Hello!
I’m trying to change layout of related products view as it would show 3 products in one line, but can’t really achieve that.
All related products on single product page somewhy are displaying in one column, and there is nothing I can do about it.
May be you could help me…

https://www.mate-tee.lv/?product=%D0%BA%D0%BB%D0%B0%D1%81%D1%81%D0%B8%D1%87%D0%B5%D1%81%D0%BA%D0%B8%D0%B9-%D0%BC%D0%B0%D1%82%D0%B5-amanda

I’m using child theme of WordPress 2012 theme and I tried to add code lines in my child-theme’s function.php file, but it does not worked for me.

function woocommerce_output_related_products() {
woocommerce_related_products(3,1); // Display 3 products in rows of 1
}

I have latest at this moment woocommerce plugin (2.1.12) and wordpress (3.9.2) versions installed.

Please help.

https://www.ads-software.com/plugins/woocommerce/