First, let me tell you something Rabbi Dr. Mordecai Finley teaches every year: the Halacha police are under-funded. Please engage in ritual however you find it meaningful.
Traditionally, the Omer must be counted every day. And by every day, I mean every Jewish day – which begins after sundown and continues through the next day. In order to “count,” one must recite the blessing while standing at night. If you forget, you can count the Omer without the blessing during the day of that Omer. If you completely forget, game over. No more Omer counting for you. Re-read my first paragraph.
So, how to perform the mitzvah? The easiest way to begin is to follow Rabbi Finley’s annual Omer calendar (pdf).
I also use the Meaningful Life Center My Omer app and the Chabad Omer Counter app. (I tend to prefer the Omer Counter, but it was glitchy starting this year, probably because Chabad doesn’t think you should use technology on Shabbat or a holy festival day.)
There are also books that can help you with the meditative aspect of each permutation of the seven lower sephirot. The Meaningful Life Center book is basically a paper version of what is available on their website / in their emails (although perhaps the emails are now not available for free). Last year, my friend, Israel Sushman, recommended Rabbi Min Kantrowitz’s Counting the Omer: A Kabbalistic Meditation Guide. This seems like a good resource. To be honest, I am trying to meditate my way into each day before reading other people’s thoughts in an effort to bring forth my own understanding of each day as it arises. In this, I have been aided by reading Gershom Scholem’s Major Trends in Jewish Mysticism and Moshe Idel’s Kabbalah: New Perspectives.
Additionally, my meditation draws upon over a decade of studying at Ohr HaTorah with Rabbi Finley and my courses at the Academy for Jewish Religion, California with Rabbi Ronnie Serr, Dr. Tamar Frankiel and Rabbi Dr. Tal Sessler.
A sephira means a number. Each sephira has hundreds of years of meaning poured into it. There is no one absolute definition of a sephira, or the sephirot (plural version of the word). The names are placeholders for larger, deeper concepts. Every system can be transformed by the people and communities that use it. And each year, as we grow, we bring a new version of ourselves to this spiritual process. May your counting help you become truly liberated, and deeply held in the matrix of the universe.