I need it to be explained in step by step to help me understand the concept

he fixed overheads for Euro are 24 million per annum, and monthly production varies from 400,000 to 1 million hours. The monthly overhead rate for fixed overhead will therefore fluctuate as follows: Overhead expenditure that is fixed in the short term remains constant each month, but monthly production fluctuates because of holiday periods and seasonal variations in demand. Consequently, the overhead rate varies from 2 to 5 per hour. It would be unreasonable for a product worked on in one month to be allocated overheads at a rate of 5 per hour and an identical product worked on in another month to be allocated at a rate of only 2 per hour