How to create multi-line orders in sandbox ?
In order to test the multi-line order functionality in sandbox, please follow these steps :
1. As a seller, list a few non-immediate payment items i.e. list item with AutoPay set as false.
2. As a buyer, click on Buy It Now and then Commit to Buy. Do not complete the checkout.
3. Now again buy the other item by clicking Buy It Now->Commit to Buy and proceed to checkout
4. At this point, all the above items will be shown in the payment page and you can make a combined payment for the items, creating a combined order.
Note : Please note that this can only be implemented for non-immediate payment(AutoPay=false).