About The Dragon balls
Earths Dragon Balls
You must collect all 7 of the Dragon Balls.
With all 7 Dragon Balls in your possesion, you must say "Arise Dragon".
Shenlong, the dragon can only grant you one wish, but it can't be beyond the power of the creator (Kami-Sama).
If the creator Kami-Sama or Piccolo dies, the dragon balls turn to stone and become useless untill one of them is wished back to life by the Namek Dragon Balls.
After your wish is made, Shenlong will disapper and the Dragon Balls will turn into stone and scatter themselves across Earth.
The Dragon Balls will remain in stone for a period of one year.
You can wish people back to life if they didn't die of natural causes. Or they haven't died once before.
(Later they get upgraded by Dende and the dragon can grant 3 wishes instead of one.)
Namek Dragon Balls
You must gather all 7 of the Dragon Balls.
You must say the password in Namekian language to summon Porunga.
Porunga can grant you 3 wishes within his power of the creator (Gurudu).
Just like the Earth Dragon Balls, the Namek dragon disappers, the balls turn to stone and scatter themselves across Namek, except the waiting period is 130 days.
You can wish people back to life as many time as you want, if they didn't die of natural causes.
You can revive only 1 person per wish.