So i have this problem that ive come across,

A mass weighing 16 pounds is attached to a spring whose constant is 8 lb/ft. The medium offers a damping force that is numerically equal to 4 times the instantaneous velocity. The mass is initially released from a point 2 feet above the equilibrium position with a downward velocity of 1 ft/s. Determine the equation of motion.

in studying for my midterm. I can't figure it out for the life of me. I dont even know where to start. I could really use some guidance please.