Before you can use Padlet, you must go to Padlet.com and click "Sign Up for Free". Then, click "Sign Up Using Google" and click your HPCSD.org account. This will automatically create an account for you, and it allows me to see the work you're posting there so that you can get credit. It will link to your Google Classroom account, as well.
*Note: If it asks for payment information, go back and make sure you clicked on the "Basic" plan if prompted.