If you do not know how to use the self-serve register at the grocery store, please use the regular lanes. Don’t try it. Just don’t. You will piss off every single person in line behind you. Also, especially don’t try this if you have a full cart. And you brought your own bags. Which you will not pull out to start filling until after you’re done “scanning”* your items.
*making the attendant help you with every. single. scanned. item.