Jan 13th.

I learned about the production distribution chain that includes Manufacturer, wholesaler, Retailer, and customer. And how all these operate in a business. From manufacturer to consumer.

Also about finding suppliers and where to look for them because thats another piece that's important to find the perfect supplier for all your needs that then you give out to the market.
I actually use this already because I buy items and resell them on eBay and sometimes I even double my earnings on some products.