In order to send email campaigns, it is necessary to have email routing credits. If you do not have any routing credits, you will still be able to create a campaign but you will not be able to send it.
You can view your credit balance from the account settings.
If you do not have routing credits yet, you can buy them by clicking directly on the "order" button next to your credit balance on your dashboard, or from the settings of your account, in the "Account" section and then in the "Offer" menu.
Your credits will be made available instantly after your purchase and you will be able to start sending emails directly.
To start creating an email campaign, go to your Dashboard and click on the drop-down menu "Create a campaign" then "Email".