If you want to add magazines to your WEBKiosk or APPKiosk you need to connect a collection to that WEBKiosk or APPKiosk. The collection can contain multiple sections, which each can contain multiple magazines.
Go to "My magazines".
At a collection click on "Edit" and "Connect collection".
Choose your Kiosk and connect the collection to the Kiosk. Now you can use that collection in the Kiosk.
Here is a tutorial about the WEBKiosk editor