You meet Sapera in two places. They work on the same data but are built for different jobs.
Point of Sale (the checkout) is the screen for daily service in the store: sales, returns, payment and end-of-day. It is built to be fast to use in a busy day at the counter.
Read more in Point of Sale.
Shop Manager is the "back office": here you manage products, prices, customers, suppliers, purchasing, sales and accounting. This is where you set things up and follow up on operations.
Read more in Shop Manager.
Everything you do in one place is immediately available in the other. Create a product in Shop Manager, and it can be sold at Point of Sale. Sell at Point of Sale, and inventory and accounts update, which you follow in Shop Manager. You are working on the same business — just from two entry points.