...
Below the search on the right side you can find a button "Not listed articleUnlisted articles" - as far as you have been granted the respective right the administration.
In the next menu window you can place a request or direct order to the supplier. The supplier receives the request and can place a special article for you.
You would like to know which requests on articles that are not listed you already placed? Then go to the Order status and afterwards on "Not listed Unlisted articles".
You will get a full list of all your requests and orders.
...