For the first option you would just add this PHP:
add_filter( 'woocommerce_product_tabs', 'woo_remove_product_tabs', 98 );
function woo_remove_product_tabs( $tabs ) {
unset( $tabs['reviews'] ); // Remove the reviews tab
return $tabs;
}
The second option you would simply copy and paste the code that site provides.
OR if you want you can add this CSS to hide the Tab:
.woocommerce #content div.product .woocommerce-tabs ul.tabs li.reviews_tab {
display: none;
}