Yep, it's sum up, all the details come with it.
But, basically you connect to the device via Blue tooth using the app on your phone.
You also need obviously to turn location on and mobile data.
Enter the price your charging on your phone, the machine then shows the amount and awaits either contact less tap from card or enter card and use chip n pin.
You then have the option to send a receipt to their mobile or email address, ut most just want to skip this as it will show on their statements anyway.