1. Library -> Particle Emitters -> Glitter Sparkles -> Apply
2. Open Layer Panel
3. Delete bottom 2 layers
4. Click on Glitter Sparkles main layer group
5. Go to Inspector tab -> Emitter tab
6. Set Shape to Line
7. Set Start Point X to -(1/2 of the size of your canvas)
8. Set End Point X to 1/2 of the size of your canvas.
9. Change color over time features to suit your color needs
10. Adjust Life parameter to suit your needs.
I've attached a render of what it might look like.