How to Add Collection Page Navigation in Shopify Warehouse Theme

Collection page navigation shows shoppers a list of related or sibling collections while they browse — a native Warehouse feature that matters a lot for a large catalog split across many sub-categories.

Steps

In your Shopify admin, go to Online Store > Themes and click Customize on Warehouse.
Switch to a Collection template using the page picker.
Select the collection navigation section or block (may be part of the sidebar filter area).
Choose which collections to list — Warehouse may pull this from your navigation menu structure or let you pick manually, depending on the setting.
Click Save.

This is one of the genuine advantages of a paid theme like Warehouse — Shopify's free themes have no equivalent, so a store on one of them needs a manually built Collection list section instead, which only works as a static homepage block, not live navigation on every collection page.