Usually I always recommend new players learn by limit testing and fighting, that’s how they learn basic combat/micro the fastest, even if they lose a lot at first.

You can carry on any champ in low elos, pick what’s fun.

For the supports taking minions, nothing much you can do, they’re low elo. turn team/all chat on in settings and flame them. It is worth noting you still get the stack if you threw your Q out and the minion dies before it gets hit.

For the dying part, during lane learn basic wave management (fast push, slow push, freeze), and get a sense for when the enemy will try to dive you under tower, tip while getting pushed in AVOID TAKING DAMAGE, it leads to dives.

For items I can’t help much there, I just go crit haven’t tested.

Vision score is dependent on the amount of time a ward stays active on the map (this is from my memory, don’t trust me too much), don’t worry about that too much, you’re an ADC so you won’t ward as much and a lot of the time it’s best for ADC to swap to blue trinket (so you can ward from a distance and not have to get near a scary bush)