How to edit woocommerce sub-category page

You would need to override the template in WooCommerce which displays the category page and add in your own sidebar / html.

woocommerce/templates/archive-product.php

You can read up on how to do this here:
https://docs.woocommerce.com/document/template-structure/

Don’t forget to add theme support in your functions.php file too.

function mytheme_add_woocommerce_support() {
    add_theme_support( 'woocommerce' );
}
add_action( 'after_setup_theme', 'mytheme_add_woocommerce_support' );