To upgrade any plugin manually from the WordPress admin dashboard, follow these steps in your WordPress backend:
1. Navigate to the left menu and select Plugins -> Add New Plugin.
2. Click the Upload Plugin button.
3. Select the downloaded plugin .zip file and click the Install Now button.
4. On the following page, click the Replace current with upload button.
5. Wait for WordPress to complete the installation.
Once the installation is finished, the plugin will be updated to the latest version.