Pay method plugin

Hi,

I am developing a payment plugin. how to manage below URL. once success have to redirect order complete page. if not failure of the transaction to try other payment option ( payment selection page). how to setup the below url for nopcommerce 4.2

    'MerchantHomepageURL':'https://www.mycompany.com',
    'SuccessURL':'https://www.mycompany.com/Success',
    'FailureURL':'https://www.mycompany.com/Failure',
    'CancellationURL':'https://www.mycompany.com/Cancelled',
    'NotificationURL':'https://www.mycompany.com/nudge

Have you looked at the source code for the built-in PayPal Standard plugin?