1) http://www.weldingtipsandtricks.com has instructional FCAW videos with great arc shots, lighting is perfect so that you can see any gun manipulation, and the shape and placement of the arc.

2) Search this forum for FCAW, there has been many hours of discussion regarding setting up FCAW and achieving spatter free code compliant welds.

3) I have two comments regarding FCAW, since FCAW seems to get a bad rep regarding spatter and clean up after welding.
          A) Spatter is caused by too much WFS for the voltage
          B) Spatter is caused by too little voltage for the WFS

There are no "Study materials" for certification that are as valuable as instructor led guidance during hands on practice.

You very well may see some great videos etc...  You need an understanding of the process, the variables and how they affect welding, and MOST OF ALL, some welding time under supervision of an instructor that cann reinforce the theoretical topics related to the process.

The above is just an opinion of one man, so treat it as such.

I doing a course (GMAW) and in our institute, they are offering courses for FCAW  http://www.weldtechtraining.com/welding-courses/customized-welding-courses/fcaw/f-c-a-w-flux-core/. You can check this if you wish to get training.