I reset an old collection page into a new name, and added some new products under it. But later I found those products will only be shown by searching it, or from the image icon at the main page. If I select the brand name from the menu, they will not be shown. It will be great if any one can help on this sitution.
I think your product might not be properly linked to your store’s menus.
Please check if the collection is added to your store’s navigation. You can do this by going to your Shopify admin and navigating to Online Store > Navigation. From there, select the menu where you want the collection to appear and add a link to it.
If possible, please share your store URL so I can take a closer look.