Issues in making shopping cart

I recently enable shopping cart for website.
I got this message when I click on Place order:

What should I do nw?

Please set default Warehouse in the Item master, or atleast in the Stock Settings.

Stock > Setup > Stock Settings

After updating default Warehouse, try completing order from Customer Portal.

Is It r8?

Select a child warehouse, like Stores, Work in Progress, Finished Items etc.

In stock setting or website warehouse?

Stock Setting (default warehouse should be a child warehouse instead of for example the “All Warehouses - P” in your graphic above)

I did… but still getting same message on screen.

Check if your website warehouse is a child warehouse as well

how to check it? where it is? i mean in which module

type “warehouse tree” in the magic bar