Direct To Amazon Forecasts

Direct To Amazon Forecasts are a combination of Forecasts and Replenishments. With a Forecast, you are running an inventory/sales report on your MF Inventory and determining how many items to order into your warehouse(s) from your specified vendor(s). With a Replenishment, you are running an inventory/sales report on your FBA Inventory and determining how many items you need to send into your FBA Source from your MF warehouse.

With a Direct To Amazon Forecast, however, you are running an inventory/sales report on your FBA Inventory and determining how many items you need to send into your FBA Source from your selected vendor. The basic process is:
1) You run a forecast 
2) You send purchase order to your vendor
3) They prep items for shipment
4) You create Amazon Inbound Shipment(s) from within your Purchase Order and send your vendor the shipping labels 
5) Your vendor ships to Amazon for you.

Here's a little more in-depth guide:

Start by clicking on Inventory -> Forecasting, like you would for a normal forecast. However, this time you'll check the Forecast using FBA inventory, vendor sends straight to Amazon checkbox and then select the Amazon Integration Config you want to use for the report.

After you create the Forecast, you will decided your order amounts accordingly and create a purchase order for your vendor. Once you issue the Purchase Order to your vendor, you will see the below link appear at the top right of your purchase order. 
NOTE: You can also create a Purchase Order from scratch, selecting and FBA Inventory Source as your destination, if you want to skip the Forecasting part.

This purchase order can now quickly be converted into a Replenishment and Amazon Inbound Shipment(s). You can either start this process now or after your vendor has prepped and packaged the items, as you will need that information before you can finish your Amazon shipments.

When you click on Create Amazon Inbound Shipment, you will be prompted with the following:

Who will prep the items refers to if you (Seller) will label, polybag, otherwise prep the items, or if Amazon will prep.

If you check the Will any items be case-packed?  box, then you will be redirected to a modified Replenishments page where you will need to input how you will pack the items. In short, case-packing is if you are sending in 100 units of SKU-123 and they will be packed 10 to a case (with no other SKUs in that case), then you are case-packing. If you are not case-packing for any items, you will be redirected to your Amazon Shipments.

If you are unclear on any part of Replenishments or Amazon Inbound Shipments, most of your answers can be found in this article.