If you not seeing your instances in the SSM management console, I would recommend looking at the prerequisites seen here:
Prerequisites for using Systems Manager
- Create an AWS account and configure the required IAM roles.
- Verify that Systems Manager is supported in the AWS Regions where you want to use the service.
- Verify that you are using supported machine types that run a supported operating system.
- For EC2 instances, create an IAM instance profile and attach it to your machines.
- For on-premises servers and VMs, create an IAM service role for a hybrid environment.
- Verify that you are allowing HTTPS (port 443) outbound traffic to the Systems Manager endpoints.
- (Recommended) Create a VPC endpoint in Amazon Virtual Private Cloud to use with Systems Manager.
- On on-premises servers, VMs, and EC2 instances created from AMIs that are not supplied by AWS, install a Transport Layer Security (TLS) certificate.
- For on-premises servers and VMs, register the machines with Systems Manager through the managed instance activation process.
- Install or verify installation of SSM Agent on each of your managed instances.