How do I look up my company's income from back in the year of 2020?

There has been a breakdown in my business and prior bookkeeper have ran a scam within my business in keeping many things in the dark without my knowledge. It's complicated and so now I am having to await some legality matters to dig into my company's file for everything that I have not known since 2016. I am fairly new to using QB on and off. I have some questions as to how to use QB as beginner. Can someone help me please to how to look up my company's income from year 2020 and where to navigate info on my QB Online?