If you don't have an e-commerce store and don't have any products yet, you can head on over to your Online Dashboard to start creating products by following the steps described in this article:
Log in to your Online Dashboard and click on "Assortment" in the left-side column
In the drop down menu, select "Products"
Click "+ Add product" button to add product
A blank product form will appear. Fill out the form with any relevant information you wish to have on the product. Here, you can categorise, select add-ons, choose your tax rate, choose variations of your product, assign product to store
If you have Advanced or Pro Subscription, you can also manage your product stock
Click the "Save" button at the bottom of the page to save your product
Your new product will automatically appear in the POS. If it isn't, go to Settings > Account > Refresh Products