On the Acronis Web site, log in to your account (create one if you are not registered yet) and navigate to Online backup > For Business. This is your account management Web page. Here you can buy subscriptions online or get trial ones. The newly obtained subscriptions are listed as available subscriptions in the Manage Subscriptions tab.
If you purchased your subscriptions from an Acronis partner, add the subscriptions manually using the I have a registration code link.
Next, install Acronis software (if not yet installed) and assign each subscription to a machine. The subscriptions become activated. After that, you can start backing up to Acronis Online Backup Storage.