Can someone explain to me the diffrence between latte, cortado, cappuccino and flat white as simple as you possibly could?

I just started my very first job as a barista just afew days ago (no prior job experience in anything before it)

and im still learning, but one thing i never understood is the difference between these four

i found this picture online, and it literally says that both flat white and cortado are the same, also latte and cappuccino

one thing i noticed is that it seems like flat white has more milk, compared to cortado? (and latte has more milk, compared to cappuccino, seems like it)

also another question, to make a whipped milk with foam, i need to steam the milk for longer, right? until it become thicker?

how many seconds do you wait until you stop the steam to make the milk for the latte? (or cappuccino?)