As with normal text links, your presell pages are hosted as static html content. Therefore results need to be tracked by you the client.

To track traffic from your hosted content you can research your referrals from your web analytics program (as your presell pages give you additional SERP entrypoints) as well as the direct impact on your ranking.

For tracking progress in rankings for your keywords at the major search engines, you should note that the time to see results can vary. I always recommend clients keep the ads in place for 2-3 months at least to see the full effects of the presell pages. This is due to most link juice filters depending on YOUR domain as well as the linking domain. Not even a link on a 20 year old domain will give you a boost overnight as it did some years ago - but it will once the links have aged.

A special note on the trust rank factor of your content hosting campaign:

Getting links from old and trusted domains will help your own domain to increase it's own trust rank. This means, that you should also get more benefits out of your previous or ongoing linking campaings. Therefore presell pages not only work as a standalone tool, but as a "moderator" for other link campaigns.