pjcdn has already left great link with indepth details. Just wanted to point out if you are using the app and you click on Selling, under Tasks it should show you second down, "Send offer to buyers", on the left would be the number of qualifying watchers/buyers and if you click on the arrow on the right it shows which items (which in my case are the watchers on my Buy it Now items (I do a lot of auctions and it doesn't apply for those watchers) and you can do it that way also.