This is the lesson people skip and then pay for. Every later lesson assumes a set of accounts with credit on them, a set of programs on your machine, and every password and key kept somewhere you can find it again. Do it once, in this order, and you never think about it again.
Two kinds of things get set up: desktop programs, free and installed with one command each, and web services, which hold a card and bill per image, per second of video or per upscale run. Programs first, because this page is the only place in the whole course where you type a command yourself. Everything after it happens in a web app you sign into, or by asking Claude Code in plain English. Prices are the official pay-as-you-go rates at the time of writing; they move, and where I had no reliable figure I say so.