Where you booked it isn't the issue. It depends on what kind of ticket you booked. Some third-party sites sell special fares, such as consolidator fares, that are not eligible for miles. If you don't have one of those, just proceed as in the above posts. For that matter, don't worry about what kind of fare you have; do as they suggest, and if you happen to have an ineligible fare, you just won't get any miles. If your fare is eligible for miles, you'll get them.