For browsers and workplaces where the extension stores are blocked. It works exactly the same way once it is running.
Your Documents folder is fine. Do not leave it in Downloads and do not move or delete it afterwards. Chrome loads the extension from wherever this folder sits, and it stops working the moment that folder is gone.
Paste chrome://extensions into the address bar and press Enter.
The switch is in the top right of that page.
Press Load unpacked, then choose the folder you unzipped: the one with
manifest.json directly inside it, not the folder containing it.
Alibaba Scraper appears in your extensions and is ready to use.
Your browser treats a copy loaded from a folder as a different extension, so it starts with its own settings and its own sign-in. Nothing is lost from your account — your plan, your history and your email are all on it — but this copy opens signed out and empty, and rows saved in the old copy stay there.
Could you use a store instead?
If the Chrome Web Store or Firefox Add-ons work where you are, use one of these instead. They install in a click and they keep themselves up to date.