To answer your first question, "Nothing." Onto your second question. If you can generate a lot of traffic to your Hub where you have placed Amazon.com Ads, Google Ads, and HP's Ads, and someone just happens to be drawn to that Ad, you might generate a few penny's.
If someone buys an item from Amazon after clicking on the advertisement from your particular site, they split the profits with you.
If someone clicks an Ad by Google, the split the profits 60-40 with you. So, if that Advertiser paid Google $.01 for every time someone clicks their Ad, Google will pay you $.006 and keep $.004! Of course some Ads pay less than that, some pay more than that, you have no way of knowing which pays what.
You get a payout with Adsense when your account hits $100.00, which means within your Hub, your G. Ad, will need to draw 16,666 clicks before it will reach $100 and a payout. Thus, you can see the need for hundreds of Hubs, with hundreds of Ads, drawing thousands of clicks, before you will generate any significant income. This usually takes anywhere from two years and up to accomplish.
Thus, the reason they tell you up front that HP is not a "Get Rich Quick" scheme. If you love to write, know how to do SEO well, and are willing to put in the time it takes, you can eventually generate income with HP, many are doing just that, but understand upfront it takes a lot of work to do so.