Use this tab to view and also define assortment structures. When defining assortment structures you may use existing parts or create new parts in the part catalog via this tab. However, when you delete a part through this tab it will not be removed from the part catalog. You can drag and drop nodes, along with their sub nodes, to move them within a structure. You can also use this tab to create parts per site.
For the description of each tab in the window, follow the appropriate link: Node Information, Connected Parts.
Basic Data, Assortments and Site Clusters
Define Assortment Node
Connect Part to Assortment
Create Parts per Site