Sometimes things only make sense when you do them. My suggestion is to just start and follow the pattern and see how it works out. I think that as you go along it will make sense. You don't need to worry about how many repeats...you just keep going until you run out of stitches. The pattern actually states it's worked from the top so that's what you'll be doing. The top edge will get longer with every row you work.
As I'm previewing, I see that salmonmac has already replied. She's smarter than I am and knows much more about knitting. If anything I wrote is other than what she said, I'd go with her.