First, I top up my car with petrol.
Next, I get paraffin and get sprayed by another customer.
Finally, I put my car through the wash.
In Japan, paraffin heaters are very common and given the surprise by my friends outside Japan, I will make a video on the topic soon.
Regarding the machines I used for fuel, first I scan a discount ticket, then I select payment method, then I insert my points card, then I choose a set amount in either yen or litres. When paying with cash, the fuel pumps only accept multiples of ¥1000. If the dispensed amount isn't a multiple of ¥1000 and we need change, the machine doesn't give change but instead issues a ticket with a barcode that we need to scan at another machine elsewhere at the gas station to get our change. It certainly isn't efficient and adds extra hassle to the whole process so I usually stick with multiples of ¥1000.
The car wash machine is similar but it accepts payment in multiples of ¥100 coins and ¥1000 notes/bills.