You will find response to all your questions in the help section of Adwords, it explains it much better but here is a few answers:
Placement url is the url you want displayed on Google, destination url is the actual url you want people taken to when they click your advert.
the rest I think you are better off reading in the Google adwords help pages
Placement url is the url you want displayed on Google, destination url is the actual url you want people taken to when they click your advert.
the rest I think you are better off reading in the Google adwords help pages
