Harmonic Motion Trig Problem Help me.?

A weight attached to a coiled spring is pulled down a distance of 10 inches from its rest position, then released. uming the motion is simple harmonic with a period of pi/3 seconds, find the equation that describes d(t), the distance of the object from its rest position at time t. ume that the positive direction of motion is down. This is the problem, please show work and try to explain a little of what you did. Thanks