Go to your "Manage FBA Inventory" screen inside Seller Central.  Now, when looking at the screen, off to the right there should be some numbers:

Inbound
Available
Unfulfillable
Reserved
Are there any numbers there (other than "0") for those products?

If so, do they have a drop down next to the number?  If so, click on each of those dropdowns and it should explain where everything is, now, this is assuming that the products are at least inbound to FBA.  If something is not inbound yet, then there won't be any information there at all.  

You can tell what is inbound into FBA by looking at your shipping plans.

Under Inventory, go to Manage FBA Shipments.  There will be a "STATUS" for each shipping plan.

If you don't see a shipping plan for the products you are looking for, then the products have not yet been received into the warehouse.

If you see a status of "IN-TRANSIT", there should be a "Track Shipment" option.

If you see a status of "RECEIVING" it should also show how many have been received, and that number will update as receiving continues to occur.