I was unable to install extension. When I went to magento admin system-> magento Connect-> Magento Connect Manager, the page showed "Error 403 - Forbidden You don't have permission to access the requested resource. Please contact the web site owner for further assistance." Therefore I can not install through magento admin.
Then I tried another way. I downloaded the extension and try to install through fileZilla. In the downloaded folder of extension, there are a fold called app and a file called package. However, when I tried to upload the app folder and package file through fileZilla to public_html, filezilla asked me to rewrite the folder app or not.
I failed to try both two ways. Is there anyone can help me out? The extension I am trying to install is facebook pixel and my magento version is 1.9. Please help me out.