For advertisers
Open a space's sign-up link, and you'll see its size, its price per day, and — if it shares its slot with others — an explanation of how display time splits by rate. Submit a short text ad or an image, an optional link for clicks to go to, and a daily spend cap (a safety ceiling; it defaults to the space's asking price).
If the space auto-accepts, you'll go straight to payment. Otherwise it's reviewed first, and you'll hear back on your dashboard.