If you are a new user of Google API please go to:

http://adwords.google.com/select/ApiWelcome

Enter your current My Client Center login email and password. If you don't have one, enter your AdWords login.
After logging in you will go to the page below:

Please select your currency and API budget also enter your company details.
Next page you will be asked to provide an e-mail address to log-in to the My Client Center:

Please provide an e-mail address or click on "Use an existing Google Account to log into my client center"
We recommend you to Create a new Google Account to log into "My client Center"
After providing e-mail address you will be taken to following page:

Please note that to be able to use your Developer (API) token you will also need to update your credit card details.
To update credit card details please go to "Billing Preferences" or simply click on the link in "pink information box"
After updating your credit card details you can enter your API token into the Bid Maximizer.