Basically, when you finding the acceleration given the mass of the object and the force that is being exerted. That can easily be found with Newton's Second Law, which is pretty much F = ma. In order to find the acceleration, we need to rearrange the formula in order to find the acceleration. Since the mass is multiplied by the acceleration to find the force. We would want to divide the m by both sides, which cancels out the mass next to the acceleration. Like so.
F = ma
F / m = a/m <--- Mass gets cancelled out as it moves to the other side.
F/m = a
Plug in your numbers and eventually you will get 6.20m/s²