How do I get ads for boosters in the game?

Hello @earmah and welcome to the wonderful King Community.  I agree that having the ability to watch ads and get free boosters would be very handy.  However, not everyone has access to this and some people who do have access may not at a later date.  The studio is always looking at ways to keep the game interesting and challenging and as a result, they will periodically pick a random group of people and give them access to an event or feature and sometimes they will remove access to a certain event or feature.  In this case, you are unfortunately not part of the group that has access to watch ads. 

However, maybe sometime in the future you might get a chance to be part of a group that has access to watch ads.  I have never had access to ads in any of my King games - but maybe sometime in the future I might have access.  Happy crushing!