You can learn how the ink and water react on the paper and how to load the brush with mulitple shades of black so that you can get many shades in one stroke. After that, you can look into nature and try to figure out simple brushstrokes for various subjects. You do not need to have an art background to do this, nor do you need an ability to draw well. You can do all of this without a teacher, and if you work at it, you can learn to paint without a teacher. There are so many books, it's hard to recommend the best.
Many libraries have good collections.
The society publishes a quarterly newsletter in magazine format which includes articles about sumi-e and other things that may be of interest to the members. The society also sponsors an annual juried exhibit. There are a number of local society chapters which sponsor workshops, exhibits, paint-outs, and many other interesting activities. Membership is open to everyone.