Its my first time in A'dam and I am arriving on a sunday in July, whats the action like in the 3 areas on sunday afternoon?

the same as any other day in the week!

I only visited the Wallen on a Sunday night. But I overheard some people saying that Sundays are the busiest nights there. After all, isnt everything else closed?

On a sunday in the summer it depends also on the weather, if it is really warm there might be not much action in the afternoon.

Still girls will show up in the evening as there would be many people strolling around

Raul