do you just kill online players or what

There are seven DragonBalls located on the entire world map. They all drop in random positions which players can then pick up.

The way you can see if a player has a DragonBall is when you see a DB icon on the minimap. If they are in an open area (Cannot kill players in towns such as Karin City), you can kill them and take their DragonBall.

I recommend checking out the DB Scramble thread which Tempest made as it shows exactly what strategies can be used and you might find other players who are willing to assist you on the journey!

can u tell me i hav cilcked it number of times and accept that application of dragonball scramble but still there is no dragonball on the map
can u tell me why??

The DragonBalls are located on every single map! Not just the Karin map! And you must walk to each map to see if there is one! Otherwise, if you teleport, you run the risk of not finding any!