You will find all of the answers regarding integration on this wiki page: Integrating the Publica script in your website or blog

No worries! All you have to do is to follow the steps below:
1) Sign in to your account
2) In the top right-hand corner, click on Script Management
3) Select the site name of your site (if you only have one site, choose Default)
4) Copy / Paste the script in the header of your source code
5) You're good to go!

Publica Discovery is entirely free and will always remain that way.

There is no limit to how much data can be monitored with Publica Discovery.

No, the script is asynchronous and has no impact on page load time.
One of the key metrics provided in the user interface is how page load time is impacted by ad blockers.
You will be able to monitor the impact of Publica on your page load time at all times and notice that pages serve faster when Publica handles ad delivery. 

To activate Publica Recovery, log in to your Publica account and navigate to Set Up Recovery in the top right-hand corner of the user interface.
You will be taken through a list of steps to activate ad block recovery.

Yes, Publica calls your ad server on the server-side and lets you deliver your direct sold or third-party ads.
Any javascript Ad is supported which includes VPAID for video.

Yes, when activating Publica Recovery please choose Outstream as the position you would like to recover.

You can also send an email to a Publica account manager who will help you complete the set up.

Sure! Check this page out: How can I monetize my Wordpress site or blog with video ads?