To install Flux Checkout, simply upload the .zip file you downloaded after purchasing Flux Checkout. Go to your WordPress admin area, then Plugins > Add New > Upload.
Alternatively, you can upload the unzipped folder via FTP to
wp-content/plugins, then activate the plugin in the WordPress backend.
After activating the plugin, you will be prompted to enter your license key. This will have been emailed to you along with the plugin’s download link.