Not accepting donations

I downloaded the plugin and when I did a test I got the following message:
The merchant login ID or password is invalid or the account is inactive.

Where do I put in this information and do I have manually add the API login and transaction key.

Also, where do I direct the confirmation page?

Here the link to my page. The form is at the very bottom. Thanks.

https://naacpcolliercounty.com/calendar/mlk/

https://www.ads-software.com/plugins/wp-donate/