I particularly recommend the following content by other writers for anyone interested in the fundamentals of haiku poetry, especially regarding haiku form: +
For those new to haiku, also consider reading Jane Reichhold’s Bare Bones School of Haiku for step-by-step lessons that will give you a good introduction to various challenges in writing haiku (be aware that some of the links in its resources section are out of date). For an overview of haiku from a British perspective (but still relevant worldwide), please visit Haiku: Another Kind of Poetry. For children and teachers, I also recommend visiting Johnette Downing’s Two Dragonfiles site (now available only through the archived site linked to here). For more on the fundamentals of the sounds (not syllables) counted in Japanese haiku, and the genre’s history, see Japanese Prosody, Haiku, and Haiku in English on Wikipedia.
For a discerning discussion on the problem of pseudo-haiku and the love/hate relationship one might have with different kinds of haiku (that is, literary haiku versus mere syllable-counting), listen to Jacke Wilson’s 25 July 2022 podcast “On Matsuo Bashō, Haiku’s Greatest Master” (the haiku part gets going with 48:40 remaining in the podcast).