Once you’re logged in, look at the URL in your browser. You should see a string of characters after .com in the URL. That string of characters is your AccountID.
In the Create Client pop-up window, enter an Application name.
Check read, write, and/or execute.
Click Save.
Once this is done, your client credentials are generated. This is the only time your client secret is displayed. If you lose the secret, you need to generate a new secret, and you will be required to update all integrations that used the old secret.