The letter is "ha", but sometimes pronounced as "wa" and can't remember the grammar rules for when that happens, sure you can tell from memory and all, but it's a pain when reading new words or reading Kanji parts:/
は is always "ha" unless it's a particle. So kanji readings? always "ha". New words (or phrases)? almost always "ha" unless it has the topic particle inside, like "konnichiWA" or "deWAarimasen" (WA = は pronounced wa)...
Thanks for reminding me that, lost all my Japanese notes last time I moved houses unfortunately so small things like that I can't find easily anymore (have to go through entire grammar books and that's IF they somehow have the info since many are badly written)
That looks like a nice site for that stuff, made do with this one earlier: https://www.japanesepod101.com/japanese-particles/ Was just stuck a bit on the pronounciation thing, I still remember all the particles, just didn't remember when ha changes to wa, I have the M2 diploma (that's what it's called here, it's the 4th one that's equivalent to Advanced), just been 6 years since so forget stuff:P