The Super Meter
The super meter is the little bar you see at the bottom corners of the screen. They build up a set amount every time you use any move, land any attack on your opponent, get hit by your opponent or block an attack.
At the start of every match, your super meter is empty. However, if your meter is filled to any extent when a round ends, you keep the amount of super meter you had in the next game.
Using up the super meter
After filling up a set amount of super meter, it will start flashing. This means that you can use an EX Special Move. Once the grey box beside the meter turns orange, it means you can use a Super Art. Once your meter is fully filled up, a flashing MAX sign indicates that it can no longer build up any more power, and you are free to use up your super meter.
Different Meter Lengths
The length of the super meter varies depending on the super art you chose before the match begins. Some are long and takes a while to fill, while some are really short. Most super meters also have multiple "layers", represented by the number next to the meter. Long meters usually only have one layer while some short bars have up to three layers.
This gives some additional depth to the gameplay, as you must choose a super art with a meter that allows you enough EX moves to the effectiveness of the super art.