> One way will be to use modulus. Check the capx.
>
i think its not related with the solution i am looking for
I think that Capx is the solution you are looking for if what you want is a add to display ever X seconds.
Just follow what they did in the capx and instead of every 2 seconds like in the capx change it to the x seconds you want, then instead of the sprite showing when every x seconds display the fullscreen ad.
If what you described is what you want then you might want to have a look at their capx they posted. unless you are just wanting someone to do the whole thing for you and im not sure you will find to many people willing to do that!