NB In this tutorial & the next one - 'Open Offer' - be aware of the navigation buttons above.
When you are asked a question both buttons will vanish indicating that they're disabled.
If you're not being asked a question the forward button will appear. Click on it to proceed to the next page of the tutorial. You'll need to do this now to continue with the tutorial.
Goods are displayed in a self-service store and customers are requested to select their own goods and pay for them at the cash desk.
'B' selects certain goods, but on taking them to the cash desk discovers that the shopkeeper will not sell them.