With "Sales Approved Item Groups" setup and assigned to the relevant Customer(s) as required, the Clever Trade Plus solution will essentially limit the Items that can be added to the Sales Order to only those setup within the relevant "Sales Approved Item Group". 

From a Sales Order if you are adding Items manually the system will check that the Item is allowed for the Customer. So if a Customer has the Sales Approved Item Group specified against them and an Item that is added to the Order is not within the specific group, the system will error, as shown below.

Reorder Items

If you use the Reorder Items feature within the "Sales Order" screen then this too will respect the setup of approved Items. The "Sales Item Reorder" screen will be shown with only the approved Items being available to select, as shown here for reference.