Before you add the endpoint into vRealize Automation you will need to setup your AWS VPC. Make sure you follow the instructions provided by AWS. Additionally you can refer to the instructions in the vRealize Automation Configuration Guide. As these may change refer to the appropriate versions for your deployment.
Adding an AWS Endpoint in vRealize Automation. Once you have logged into the vRA console go to the Infrastructure tab, click Endpoints, Endpoints. Click new+ cloud, Amazon EC2. Provide a name for the endpoint as well as your Access Key ID and Secret access key.
Next go to the Fabric Groups and add a new Fabric Group as well as an administrator and select the appropriate compute resources.
Next create a reservation by going back up a level to the Infrastructure tab, Reservations
Once you have added the appropriate resources you should be to go into the design canvas and create AWS EC2 blueprints with the resources you configured.
Remember to reference the latest document based on the version you are running as they differ slightly.