Yes, it is the simplest. But Cascade isn’t as easy as Niagara for that sorta thing.
I know, I used to love Cascade, but once I got to use Niagara, it just went uphill from there.
Anyhow, regardless, you need to specify how many Sub-UV frames you got, in my case, let’s say 3x3, so you need to specify X and Y, so 3X and 3Y and then you need to specify HOW MANY Sub-UV frames you got, in this case 8, since you gotta count 0-8 and that’s 9 frames. The reason why your particle system looks that way is because you didn’t specify the the Sub-UV matrix. Look for a Cascade flipbook particles tutorial, there’s a ton in YT. It also took awhile for me to get it, but once you get it, it’s easy. And since you’re on YT, check Niagara and compare to Cascade, I’m sure you’ll find the Niagara way simpler. Or at least I did. It only seems complex at first.