Does immersion really work?

I have seen so many people state that immersion without translation or minimal translation is really good for you. I just don't understand how. Do you really pick up words that way? How much of your time to you have to spend with that language? Everyday for hours? I am unsure and I would appreciate some clearance from people who may have tried it

Edit: maybe I should mention that I am like barely A1 and Neurodivergent and have a hard time with textbooks or other traditional learning methods