A Saiyan and a Nameck are fighting, the Saiyan goes first and can choose an attack he or she has and names it, that is the attack he is using for his turn. You then must roll a 6 sided die (refered to as D6 on this page) to see if the attack hits. (more about hitting later) If it does you then compare the power of the attack plus the strength of your character to see how much damage it deals to him/her, but before that your character can roll a die to see if he blocks the attack (this cannot be done if you are on top or behind opponent) More about blocking and such later. Then you tally the total damage on your opponent, if he is KO'd (life points 0 or below) then the fight ends and the saiyan wins! However if the blow isn't fatal then the Nameck then takes his turn to attack.
Charging Up...
Charging up is an essential part of combat online. For example there is an attack that is used by Nameck called "Ryoken". This is an attack that focuses all of a characters energy and power into one fantastic blast of raw energy that basically kills an opponent. However you can't simply go out and Ryoken your life away you have to charge up the energy within to use that attack. A GOOD Ryoken strike needs about 2-3 turns of charging before firing, in which case the shot would be nearly fatal. However if within your period of charging you block an attack or move somewhere all your charging will be lost and you will have to recharge.
Other Abilities
Certain races have their own abilities listed in the special abilities setion of their page. Such abilities are the saiyans SSJ form, the Nameck healing, and the Human Technology.