explosion timing

I tried the ipo screen and did not find any curve!
i am using the nayman explosion from http://www.centralsource.com/blender/explosions/
I assume it is particles
I need to delay the explosion a few seconds.
how do i do this?

There are no IPO curves for particles .

You can change the start/end times by going directly to the Particles panel in F7 (Object) context in the buttons window and then hitting the physics buttons icon located next to the object buttons icon both of which are right next to the context icon buttons . From the Particles panel just change the Sta: value to when ever you want to start the explosion and maybe also the End: value accordingly .

There are two spheres involved with the explosion so you will need to change the values for each separately .

Thank you very much for your very clear instructions.