To join the affiliate program you need to complete a member account application and send it to the casino. Your application will be reviewed and you will be notified whether your application has been accepted or rejected.
When you join the affiliate program and you start promoting the casino you will earn a percentage of the net revenue. Every month the balance is reset so this means there is no negative carryover.
It is expected from every affiliate to promote one or more casino brands and to fulfill the minimum requirements in terms of player recruitment. You have to sign up at least 5 new depositing customers every month. If you fail to do that for a couple of months in a row, you will then revert to the lowest revenue share level.
Unfortunately, Casino Extra hasn't offered any kind of CPA agreements since 2015.
The Casino Extra Affiliate program is called iGaming Partners and includes the following brands Lucky31 Casino, Casino Estrella, Casino Extra, and Dublinbet Casino.