Thank you for explaining! I didn't quite undestand at first... so this is the explanation for the super-dummies
As for the tamper-level: I have seen it twice and then tasted the coffee and it was good.
1:the person levelled the coffee with the tamper that is attached to the grinder, it looked like two moves with which she chopped the heap first towards herself and then the opposite side (something like S-N motion - not SNEW). And then tamped pressing the tamper with her fingers into the coffee.
2: another person levelled the coffee compresing it with a tamper (Reg Barber) and then tapped the portafilter strongly twice, so that some coffee jumped out of the basket, then tamped lightly with a polish and then tamped hard.