To update your plugin to the latest version you just new to install your newly downloaded version as a new plugin. By updating the plugin, you will not lose any changes and customizations that you have made to your site, unless you modified the plugin files.
If you can access your FTP host, you can update the plugin by simply replacing all files in wp-content/plugins/plugin_name
But if you want to make it from administration panel, follow this steps:
- In your WordPress dashboard go to Plugins > Add New Plugin
- Click on Upload Plugin button and then on Choose File button on the next page.
- Install your newly downloaded plugin.
