I was just watching it too, but not getting it. Is scoring only if you do throws?
Tournament Guide
Gives a quick breakdown
Basically you can score different ways.
If you do a clean throw on the back you'll get a full point or ippon. Or if you hold the person down for 20 seconds. This ends the match.
If you do a partial back throw like they roll onto their back you get a half point. Also if you hold them down for 10 seconds with your leg free
If you hold them down for 5 seconds you get a Yuko which is a quarter point.
The yellow boxes are penalties which is basically a minus Yuko or quarter point and count against you when they match is over. You get penalties for hands in the face or not fighting and being too defensive.
When the ref does the palm up that is stopping the match because they're out of bounds of the action is at a standstill without any hope of scoring.