Step 1 : Click on Inventory and Plan items

Step 2 : Click on Basket Management 

Step 3 : Create a Basket with a name as shown below 

Click on ADD BASKET and then enter the name of the Basket and click on SAVE 

Step 4 : Once the Basket is created, here for example we have created a basket for example " ALPHA " as shown below 
              Here you can map the Vendor item with a plan item in the Basket " ALPHA " 

Add a PLAN ITEM to the basket as shown below 

Add a VENDOR ITEM  to the basket as shown below