When viewing your domains page in the Acquia Cloud UI, you may notice two IP addresses and a CNAME when previously you may have seen just one IP address for your other applications.
For applications with two IP addresses, you should add both these as A records with your DNS provider. Alternatively, you can add just the CNAME record at the DNS level, but be advised this may not be compatible for bare (non-www) domains. To verify this, please check with your DNS provider.
At the time of writing, new Acquia Cloud Enterprise applications are provided with Network Load Balancers, each of which is given its own unique IP address and provisioned in separate availability zones.