Just having a fare basis is not enough. You must meet all of the requirements and restrictions in the fare. You must be eligible to buy that fare. There must be appropriate inventory available to use that fare on the flights you want to take. All of these items can be researched on ExpertFlyer; it involves more work than just finding a fare basis you like.

If your goal is just to find the cheapest fare for a certain flight, Google Flights will suit you better. EF is more about finding out why a cheap fare is not available for your desired travel dates, and what you need to change in your itinerary to get the cheap fare (if at all possible).