@Abhi_R, you are referring to the differences between accrual and cash basis accounting. See this Guide on how to change:
https://forum.manager.io/t/choosing-accrual-or-cash-basis-accounting/7129
But before you can do anything, you need to understand the fundamentals of double-entry accounting. Just as in your construction business, Manager is a tool. Using tools when you don’t know what they are supposed to do often creates trouble. I recommend starting at http://www.accountingcoach.com.