Please help me obtain the objective function, reestrictions and variables.

The demand for a special small engine over the next five quarters is 200, 150, 300, 250 and 400 units, respectively. The manufacturer supplying the engine has different production capacities estimated at 180, 230, 430, 300 and 300 for the five quarters. Backorders are not accepted, but if necessary, the manufacturer can use extra time to meet immediate demand. The overtime capacity in each period is half of the regular capacity. Production costs per unit in the five periods are $ 100, $ 96, $ 116, $ 102, and $ 106, respectively. Overtime production cost per engine is 50% higher than regular production cost. If a motor is produced now for use in later periods, an additional storage cost of $ 4 per motor per period is incurred. Formulate the problem as a transportation model. Determine the optimal number of engines to be produced during the regular time and overtime for each period.