FORS. Front Opposite, Rear Same
To change the point of impact, you adjust the Front sight in the Opposite direction you want the point of impact to move on the target.
To change the point of impact, you adjust the Rear sight in the Same direction you want th epoint of impact to move on the target.
Since your pistol is shooting left, you would want to move the front sight to the left to move the point of impact to the right on the target. However, I don't think that the front sight is adjustable on that pellet pistol.
So, to move the point of impact to the right on the target, you would adjust the rear sight to the right.