Animation Transition (FBX file with animation)

I have an animation sequence from a .fbx file (named Take 001) asset name 'intro' and I have created a separate asset, titled 'scanline' and it is a particle system. I'd like for that particle system (emanating from a cylinder object, mesh not rendered) to be triggered to sweep over the finished animation once the animation is complete.

Do I create states for this? or do I create a script from the original animation (the .fbx file) or the target particle system animation? Not too sure exactly where to start here, any tips or recommendations would be good on where to guide event driven (or time driven) animation.