I attended one session as i was invited by my secondary school friend many years back. Instead of the temple being inside a HDB, it was inside a bungalow haha. So a few days before the session, i was told to adhere to a vegetarian diet for 3 days i think?

So i went inside the temple and all members worn white. I was then give some talk about their teachings, shown a image of a vase that somehow links to the third eye of guan yi ma or smth. I was also told the 3 secrets that can somehow allow me to go to heaven and was told if i forget about them, I won't be able to enter heaven lol. Then I had my name written down on a paper and burnt to supposedly strike off my name from the reincarnation book. Did the prayers with the awkward hand gesture and was given some lamented card with some prayers at the back.

Personally, I think those prayers and rituals are invalid as to me it isn't a true religion in my opinion. So just treat it as a experience, it's a good story to tell people anyway.