I'm confused about how Itch works... I mean, doesn't it process donations right away, and release the payout right away?

Why do I have multiple payments there but the payouts page says I have 1...?

As explained in the Getting Paid FAQ, earnings can only be paid out after a week. And then after requesting a payout each transaction has to be manually checked, which nowadays takes another week at least. Please wait.

I wouldn't know about "payout"

As I don't have billing settings.