In order to begin customizing your Datto Drive account, you must first be provisioned on the "Professional" package.
Being provisioned can only happen through your authorized Datto reseller. If you have recently signed up to Datto Drive and are not currently linked with a Datto reseller, you must fill in the 'Upgrade' form found by clicking on the 4squared icon in the upper right hand corner of the application.
This will lead you to fill in and submit a form that will begin the process of matching you with a Managed Service Provider in your area.
If you are already working with an MSP, they can provision you in their management portal so that you are on the "Professional" package.
Once they have confirmed they have given you access, then you should be able to begin customizing immediately. A browser refresh should display the 'Datto Drive' app as shown in the above image.