Any heli with a tail rotor will try to drift.
In most model helis the tail rotor thrust to the right to compensate for motor/engine torque. One of Newtons laws come into play here.
"For every action there is an equal and opposite reaction"
The right thrust will try to push the entire heli to the left.
Using the trim switch you can attempt to correct for this by adding right aileron trim.
I try to make mechnical adjustments my self to keep the trim switches as close to center as I can.
The mechanical adjustments are screwing the ball links in or out on the servo to swashplate connections. On the ailerons on most helis with 3 servo CCPM setups I try to keep the aileron and pitch servos even by making one turn in on one for every turn out on the other.
By doing this I can keep my swashplate level with the elevator and avoid changing collective pitch settings.
As Rafael23cc said, do some reading and find out more about how your heli works. It will serve you well in the future.