[Alex_Valde]

First you'll need to make a timer like this

pawn Code:

SetTimer("OnlineTimer",100000,true);
//OnlineTimer is the name of a timer
//100000 is the time = 10 min
//false is if the timer will repeat
//EDIT: put this under your OnPlayerSpawn or OnPlayerConnect callback.

Than public it:

pawn Code:

public OnlineTimer
{
    new score = GetPlayerScore(playerid);
SetPlayerScore(playerid,score+1);
return 1;
//EDIT: Put this at the bottom of your script.
}

Untested. I hope it will work