This Site can be set as a stock location by navigating to the details tab of the site, in this case the details tab is pinned to the right hand side of the screen. Then turning on the "This site is a stock location". In the screenshot provided, this is greyed out as it is a site marked a sa stock location and there is stock located on this site, so you cannot uncheck the box for stock location.

Please remove all Products from stock to edit

We will receive stock directly into the stock location.

Click this number field. I added a quantity of 2 for this example.

There will be text to let you know that auto pick has been selected "New Asset will be allocated a tag and created".

Update Stock Quantity on the Clients Site.