Why this order
The keyboard is first because it takes two minutes and finds the fault that most often means replacing an entire top-case assembly, which is the single most expensive thing you can discover in a hurry. The trackpad follows because on many laptops it is part of that same assembly, so the two answers combine into one repair decision.
Audio and camera sit in the middle: quick, and each rules out a component you would otherwise have to take on trust. The display tests are last because they need the room conditions to change, and doing that once at the end beats doing it twice.
Core and optional steps
The 7 core steps cover what every laptop has: keyboard, touchpad, microphone, webcam, speakers and the screen, which takes two tests (one for dead and stuck pixels, one for backlight bleed and banding). The 4 optional steps only apply sometimes: an external mouse or a controller that comes with the laptop, the key code viewer for a key that types the wrong character, and the display settings. Skip the ones that do not apply; the report keeps them apart, so a skipped controller never reads as a fault in the laptop.
What the report shows, and what it does not
The report lists every part as passed, failed, skipped or not run, with the date and the browser it was made in (name and version only). A result that came from the test itself says so, and so does a mark you set by hand. It is labelled self-reported because a web page cannot prove which laptop it ran on: treat it as a record of what was checked, not as a certificate.
Print it and it fits on one A4 or Letter page, with the site header and everything else left out. Save PNG draws the same report as an image, in your browser. Copy share link gives you a link whose fragment holds one flag per step and the date, and nothing else: no name, no browser, no device details. Whoever opens it sees a read-only copy of the report, and their own stored results stay untouched.
What this flow cannot check
Three things matter as much as anything on the list and none of them is testable from a browser: battery health against design capacity, drive health and powered-on hours, and how the machine behaves thermally under load. Ask for the first two directly, because every operating system can report them and a seller who will not show you is telling you something. The third needs the machine running something demanding for several minutes, which is worth asking for on any laptop you plan to work on.
Also worth thirty seconds and not on this list: plug something into every port, and check the hinges and the charger. A browser has nothing to say about any of them.
Where your progress is stored
In this browser, in localStorage, and nowhere else. There is no account, no sync and no server that could receive it. Clearing it removes it completely: Start over deletes your marks and the stored test results in one go, and you can see the entries yourself under Application in your browser's developer tools. That is the same promise the tests themselves make, and it is why this flow has no sign-in.
Reading the results
Each test tells you what it found; the guides tell you what it costs. Start with how to check a second-hand laptop before you buy it for the negotiating view, or how to check a used monitor if the display is the whole purchase.