How does particle system work?

hey Gupta, you really need to learn how to use google.
Looking at your string of (odd) questions lately, here is how:

go to google.com

begin with “UE4”
then the subject: “Cascade” or “particle system”
Then what you want: “Tutorial”
or the problem at hand “Color over life”

so you google sentences like “UE4 Cascade tutorial”
so you get stuff like: LMGTFY - Let Me Google That For You

I also made some cascade tutorials you can check out here: