During a match, you're graded on five things: Life Bonus, Time Bonus, Perfect Bonus, Winning Steak, and Max Combo. If you get 400,000 (I believe that's the number) or more, you will be awarded with an SS rank.
Here's what I did to get it:
Set the game difficulty to "very easy"
When the match starts, immediately do Kim's QCB+HK special, which almost always knocks them down.
I then run up to time a crouching HP to hit right when they get up, and then cancel it into his QCB+HK. The computer almost never blocks it, or if they do, they don't punish it - careful to watch if they safe fall because you want to time this simple combo to hit them every chance you get.
I only got one perfect (no "need" to shoot for perfects on all three)
When I got enough meter, I went into DRIVE MODE and executed his NEO MAX super which hits (combos) 24 times - good for points.
And I beat everybody reasonably fast.
That's all it took, and it popped. You will gain meter extremely fast, so you will be able to land at least 2 or 3 NEO MAX supers. If you see the stuff at the top like "perform 3 jumps" - do it. Don't go overboard because you still want to beat them relatively fast, but doing a couple of them will build your meter really, really fast. Building meter fast = more NEO MAX/SUPER SPECIAL MOVES, which means quicker times and more perfects, if you aren't hit.