Installed wordpress plugin "Variation Swatches for WooCommerce" - Free version. 

https://wordpress.org/plugins/woo-variation-swatches/

but it doesn't work on Theme, or i can't make it appear on variable product page.

Is this plugin compatible with Gem Theme?

if Yes, then how to make it work?

if Not, which plugin can be used to have variable product swatches?

дико извиняемся, everything is working !