1) FTP the POLi plugin to the OpenCart directory
2) Log into your OpenCart admin area
3) The POLi plugin should now be visible in "Extensions" under
"Extensions", followed by selecting "Payments". Now scroll down till you
see POLi (Internet Banking) and click on the Pen action button
corresponding to the POLi Payment plugin.
4) Add your Merchant Code and Authentication Code and click the "Save" blue button on the top right hand corner.
5) Go back to "Extensions" > "Extensions" and locate "POLi Payment" and click the "+" sign to activate the plugin. If the payment has not been activated in the previous step under "Enabled POLi Internet baking"
POLi Pay is should now be live on your OpenCart site.