How do orders and commissions work?

First off, thank you for all the work you've done on Commerce Marketplace - it's been really exciting to see it take shape over the last few months.

I've been building a trial marketplace site and its brought up a few questions around how orders and commissions work (please bear with me if they are really obvious):

When a product is sold from a store, who receives the sale notification - the creator of the product or store admin? If it's the store admin, what happens if there's more than one admin? Is it possible to change who receives the notification on a per store or product basis?

Is it possible to set a commission on sales and if so, how? And, can the commission be changed on a per product/store/role basis?

Thank you!