Hi there,
the Merch Site has some custom changes built into it – including the single product sidebar – this blog post on the original import explains more:
https://gpsites.co/merch/woocommerce/
Scroll down to: Single Product Sidebar
TLDR:
1. Go to Appearance > Elements and delete the Hook titled: Woo Single Product Sidebar
2. Go to Customizer > Additional CSS and delete this:
@media (min-width: 768px) {
.single-product #right-sidebar {
float: right;
}
.single-product div.product .woocommerce-tabs,
.single-product div.product .related.products,
.single-product div.product .upsells.products {
width: 66%;
display: inline-block;
}
}
3. Set the Sidebar position in Customizer > Layout > Woocommerce