bloom switch

Hey guys I’m flipping my plants to flower, and this is my first time growing so I’m worried that I’m forgetting something. I changed the timer to a 12/12 cycle, and turned on the bloom switch on my light. Then I started reading that you should wait to turn on the bloom light. So now I don’t know...

To you experienced growers, I have read so many different opinions about using veg, and bloom switch together, full spectrum. What's your experience? You just use veg during veg? Bloom during flower, or both the whole time while growing?