Data for public firm financial model

I have encountered a problem recently. I’m trying to value public firms trough financial models. But they publish almost no information about units sold, product price, headcount, etc. Apple doesn’t even publish the number of iPhones sold. How is one supposed to make a financial model for a public company? Where do I get this data? In IB and PE, you get access to pretty much any information you ask the company, so making a model is fairly simple.