How do I learn to build a three-statement financial model?

A full three-statement model feels overwhelming because you are trying to hold all of it in your head at once. Nobody can. The people who build these do not see one giant puzzle. They see three simple statements that are joined by a few links. Once you see the links, the fear drops fast. Start with the income statement, because you likely already understand it. Then the balance sheet. Then the cash flow, which is mostly just explaining how cash moved between the other two. The magic is only this: net income flows into the balance sheet, and the changes on the balance sheet flow into cash. Learn those handoffs and the rest is detail. Build one small model this week with made-up round numbers, and force it to tie out. Ten dollars in, watch where it lands. When it balances, you will understand more from that one clean example than from a hundred you were afraid to touch. Do it small, do it whole, and the overwhelm turns into a process.