I just joined. How do I add topics?

I see that I can search for topics that I am interested in, but is there a list of topics somewhere? How can everyone list topics in their own words, and have them come together? (i.e.: I might be interested in any of the following: education, elementary education, math education, teacher training, curriculum, school administration, tutoring, Montessori, homework, learning styles, student autonomy, etc. How would I indicate a “cluster” of interests, without aimlessly listing every permutation of every word?)