API Login and Transaction Key Location

I'm sure I am missing the location of these items (API Login and Transaction Key) - but I cannot seem to find them for the Payment Form component.

I looked in both the "General" and "Messages" tab in the configuration area -- didn't see it there.
I created a new form in the "Forms Management" area -- don't see anything under the "Basic Information", "Messages" or "Field Settings" sections.

Currently I have a form that gets the below message once completed:

(TESTMODE) The merchant login ID or password is invalid or the account is inactive.

Any help would be greatly appreciated!!!

Hi

Please go to Payment Form -> Payment plugins, click on the os_authnet plugin and you will be able to enter API Login and Transaction Key of your authorize.net account .

Hope this help !

Tuan