[Ahmad45123]

First of all, This isn't a place where you request code... here we help you with your already writenn code.

However, Here you go:

PHP код:

//This is just some useful defines for time converting.
#define S_TO_MS(%0)            %0 * 1000
#define M_TO_MS(%0)            S_TO_MS(%0 * 60)
#define H_TO_MS(%0)            M_TO_MS(%0 * 60)
//This will be anywhere you want the timer to run.
SetTimerEx("DescreaseWantedLevel", M_TO_MS(10), 1, "d", playerid);
//This will be anywhere in the script.
forward DecreaseWantedLevel(playerid);
public DecreaseWantedLevel(playerid)
{
    SetPlayerWantedLevel(GetPlayerWantedLevel(playerid)--);
    return 1;
} 


And about textdraws, Search... There are tens of tutorials and editors about it.

E: Oh and also as Azula said, Make sure you delete the timer OnExit.