Download the latest version of the plugin as a generic zip file. This is safe for testing.

Locate the downloaded unflatten-plugin.zip file and unzip it. You should see a folder containing manifest.json and other files.

1. Open the Figma Desktop App.
2. Create a new design file.
3. Go to Plugins > Development > Import plugin from manifest...
4. Navigate to the unzipped folder and select the manifest.json file.

The plugin is now installed! You can run it by searching for "Unflatten Paster" in your plugins list or by pressing Cmd+/ and typing the name.