questions about tarot from an early beginner

so i’m very new to tarot, but i’m really interested in it and want to learn as much as i can. i’ve noticed a few things that people do with tarot that i never see get explained in videos of it, so i decided to see if anyone here can explain here! 1. what purpose do crystals hold when using/reading tarot, and how is their use different compared to just carrying around crystals? 2. where do the specific readings in tarot come from? your higher self? the universe? a deity? 3. why do some people choose to keep their tarot decks in bags instead of their original boxes? 4. what are some good ways of clearing your mind and setting your intentions for tarot readings?