You must enable pretty permalinks in Settings > Permalinks.
Installation Instructions
Upload the plugin files to the /wp-content/plugins/plugandpay-woocommerce-tbc-credit-card-payment-gateway directory.
Activate the plugin through the Plugins screen in WordPress.
Go to WooCommerce -> Settings -> Payments -> TBC credit card (click Manage) and fill out required settings.
Bank provides certificate in .p12 format, to transform it into .pem use this command: openssl pkcs12 -in *.p12 -out tbcpay.pem (You can also convert certificate using online tools).
Upload generated .pem certificate to a secure directory on your server, usually this is not your root wordpress directory. Enter full path to certificate in plugin settings under certificate path.
You should communicate Ok and Fail urls to Tbc e.g. example.com/wc-api/tbc/ok and example.com/wc-api/tbc/fail. Note that these slugs can be changed in plugin settings.