Magento 1

Download and install the Zip extension

Download the Zip Magento 1 extension

You must download and install the Zip payments plugin, install it then activate it to begin accepting Zip payments at your checkout

Installation via FTP

Open your FTP client
Navigate to your root directory
Copy the files from the Zip extension you previously downloaded to your magento root directory.
Login to the Magento admin and go to System -> Cache Management to flush the Magento cache.
Follow the configuration steps.

Next Steps

Setup the Zip Magento 1 extension.

Activate the Zip web messaging on your web store.