Hello,
Thanks for contacting us.
You can install and update plugins manually via Dashboard or FTP.
Please read about the updating here – https://xstore.helpscoutdocs.com/article/37-plugins-update
In case if automatic plugin installation fails (as a rule it is because of your server settings), you can install them manually via your Dashboard: Plugins > Add New > Upload Plugin > Browse plugins archives. Or via FTP, by uploading and extracting the plugin zip files into wp-content/plugins folder. You can find the zip files for plugins installation here – https://www.8theme.com/downloads/
Regards