Woo Category Archive template tweaking (Bricks Builder)

I am converting an existing woo site into the bricks builder. It's a multi-level category site. I followed the instructions on https://academy.bricksbuilder.io/article/creating-dynamic-woocommerce-archive-pages/ and I can't get the categories to show correctly. I want to show ONLY the child categories of the current category. The instructions seem quite straightforward and I think it's something simple that's wrong (maybe the query in the parent). So probably a quick fix.

eg Shop > Category A > Sub(A1), Sub(A2), Sub(A3) + some products
Shop > Category A > Sub(A1) > Sub(B1), Sub(B2), Sub(B3) + some products

So for this example, when in category A, I want to show the 3 sub-categories + any products at that level.

I can do all the styling........ I just want the query working

(I want the shop to just display the top level cats)