There are two ways to update ‘Blog Designer Pro’ plugin.
1) Update Via WordPress admin
2) Update Via FTP/ Cpanel
Update Via WordPress admin
To update plugin via admin panel, plugin’s license key should be registered with site if you have not registered. Read this article to Register License Key.
Register License Key.
If new version of plugin is available, you will get notification to update version of plugin on plugins listing page. just click on ‘Update now’ and plugin will be with latest version.
Extract that codecanyon downloaded zip in your local PC. There are 3 items inside it.
blog-designer-pro-document.zip
blog-designer-pro.zip
Licensing
Extract the above-selected zip file (blog-designer-pro.zip). It will create a ‘blog-designer-pro’ folder with all plugin files & folder inside it. (Remember this extracted folder path)
Using your FTP programs like Filezilla or cPanel, upload the non-zipped plugin folder into the /wp-content/plugins/ folder on your server.
Go to Dashboard » Plugins » Installed Plugins page and find ‘Blog Designer PRO‘ from the plugin list.
Click on Activate to activate Blog Designer PRO plugin.
Still you not get the solution for your query? open a support ticket.