Change a Limb's Position

I want to change the player’s left arm position to another.

Multipling its motor6D CFrame by another one doesn’t work as I want it to, as a single value also modifies another one (say, if I multiply the motor6D cframe by CFrame.new(1, 0, 0), the arm doesn’t move to a single direction but to two: to the right and forwards)

I’ve tried multipling its motor6D CFrame like this

leftarm.C0 = leftarm.C0 * CFrame.new(Vector3.new(1, 0, 0))

But it’s the same, a single value alterates another one too.

Can anybody help?