In order to send any marketing pieces, you'll first need to subscribe to a product.
To sign up for a subscription, hover over your name at the top right and click My Products and Billing.
On the My Products and Billing page, review the different product options and click Subscribe Now! next to any of them or click Change my Products at the top of the page.
Go through the process to selecting your product subscriptions and click "Continue to Payment" to be taken to the billing page where you enter your credit card information.