After honestly completing the assignments of this course, you can expect to be able sit down at the organ and harmonize a non-modulating melody (like a chorale or a hymn) in the soprano and in the bass with pedals in a slow tempo using the main 3 chords - Tonic, Subdominant and Dominant.
Also you will be able to play a progression of several chords (like a cadence) in any key you want as well as play ascending and descending sequences of simple chords through various keys. You may be able to do this with a proper voice-leading in any key up to 7 sharps and flats.
You will also find that this course will help you tremendously in your quest in learning to improvise on the organ. Currently you may find that you improvise by ear (meaning that you play what sounds good) but after this course is completed, you will know what will sound good EVEN BEFORE you will play.
In other words, your mind will direct your fingers but not vice versa. Although this is not an improvisation course per se, the basic harmonic techniques will build you a solid foundation for your improvisations.
Needless to say, everything you will be able to play on the organ, you can also write on paper. I know, this sounds impossible to a lot of people to achieve in just 12 weeks, but trust me on this - with this systematic approach you can do it.
Since you are reading this post, I take that you are getting value out of my daily advice and tips and that your skills as an organist are constantly improving. But that's nowhere near the true value you can expect to receive from this course.
My feeling is that although this is only an introductory course, with the skills you will receive from it you will be better at harmony than 80% of organists currently are.
Are you excited? You should be...