I am purchasing from various suppliers, having the product sent to Preppers to tag and box per Amazon requirement and shipped again to Amazon warehouses. 

Is there a Odoo tutorial that: 

1. Shows how to upload sales before I started with Odoo?

2. Will help track inventory from purchase to sale and help calculate profit and loss from supplier to sale? I am bran new and connected the Amazon Connector and can only see the sales that are happening.