jhānas, Zen, and how to practice concentration meditation

I've read about the jhānas which one can experience from concentration (samatha) meditation. I have been practicing some form of mindfulness, breathing meditation, but have not experienced a state of absorption that is characteristic of the jhānas. I know that the jhānas cannot be experienced only by reading about them, however, the insight from my meditation practice alone has not brought me to them. From my perspective as a novice practitioner, it makes sense to look to the Zen (derived from the word dhyāna ) branch of Buddhism for guidance on the subject of meditation : > In the process of deepening meditation, one can roughly identify three > distinct stages: the stage of concentration, the stage of meditation, > and the stage of absorption. > > This dualistic relationship is broken gradually as the practitioner > moves into the stage of meditation. The ego-conscious activity is > gradually lessened, and the barriers it set up for itself will > gradually be removed. When the practitioner enters the stage of > absorption, the dualistic framing of the mind will be removed such > that the mind starts structuring itself non-dualistically. There will > be no separation or distancing between an object of the mind and the > activity of the mind itself. I don't have the budget for every book on Zen Buddhism, but I have read all the Zen books on Kindle Unlimited (the content is mostly history, terminology, and sitting accessories). What books are there that go into depth on Zen/samatha meditation practice?