It's really easy.How do get the pastry to look like that - the pattern I mean?
Lay the dough out and roll it a bit until you have a rectangle. The size doesn't really matter, but I try to handle puff pastry as little as possible.
Once you have that, take a bench scraper or dough scraper, something with a straight edge, and go along one long side, making angled cuts about a third of the way in, and about an inch apart, all along the side.
Repeat on the other long side, and you should be left with a third of the dough in the middle intact.
Spread your filling along that middle third, brush the cut edges with egg wash, then alternate wrapping them up around the filling.
I probably made it sound difficult, but it took me longer to explain than to do.
Let me know if that makes sense. If not, I'll bet I can find a video somewhere. It's really simple.