1. Download the extension and unzip it — you will get a folder called adtrust-extension.
2. In Brave or Chrome, open brave://extensions (or chrome://extensions).
3. Turn on Developer mode (top right).
4. Click Load unpacked and pick the folder you unzipped — the one with manifest.json directly inside it.
5. Open Ads Manager, click the AdTrust icon, and log in — new here? Create your account in the popup.