After getting merchant account from Nagad simply activate the plugin and go to woocommerce setting option. Select payments and manage options for Nagad Payment Gateway.

There you will find a form to put merchant id, merchant private key , Nagad gateway public key and other necessary fields.

Simply fill up the form and click save to get Nagad payment option in your website.

You need to add the callback url ‘your_website_url/nagad-pay/payment/confirmation/’ to Nagad merchant panel and let Nagad know the callback url in order to whitelist this in their server.
Also if your website is hosted from a foreign server you need to inform Nagad the server’s main IP address to whitelist from their end.