I want to take the list of users from my Duo Account and put them in ServiceNow. Please help and correct me for steps

I have followed the steps for creating Admin API from: Duo Admin API | Duo Security.
I got the integration, secret keys, the issue is:

It’s given that the username should be integration key and password should be combination of current time, method, path etc parsed with the secret key using HMAC-SHA1.
Is this supposed to be from the header for the HTTP Request for the default GET request? If yes, what should be the name of the headers?
And what all headers are required (with their names)?

A) I tried modifying the basic auth profile which is used for authentication. What should be the username and password for that? if username= integration key and password=HMAC -SHA 1 signature, how can I change it for every request if it has to be fixed in the serviceNow auth profile?