How does one Link an "Account" to a "User"? (What do those terms mean in this context)

I am trying to just get started with the Infusionsoft API bit using Get Started - Keap Developer Portal.

  1. I created a developer account.

All good.

  1. I HAVE NOT created a sandbox account. I just wanted to try out the API and hence didn’t think it was necessary to provide my card details and set this up.
    NOTE: Do let me know if the is “required” step for trying out the API.

  2. I went to “Try the API” at Keap REST API

  3. It prompted me to enter the “Client ID” and “Client Secret” (which I was able to get from See the screen shot:

  1. Upon entering the “Client ID” + “Client Secret” and clicking authorize, it took me to

On this page, I was greeted with "You need to have at least one Account linked to your user in order to grant access. ". See the screenshot:

I am stuck here. What do I need to do to “link at least one Account to my user”?

What is the “Account” being mentioned in this context?
I assume the “User” is the user whom I am logged in as.

Thank you for your patience.

You’ll want to create a sandbox account. api access must be authenticated to an actual app by the app owner. The api doesn’t have any information to work with without an app to connect to.