You can get a list of the available instance with the following command.
aws ec2 describe-instances
Or — if you like it a little bit more readable — choose the table output option.
aws ec2 describe-instances --output=table
If you are only interested in instance number name and state use grep.
aws ec2 describe-instances | grep -E -o '\bi-[0-9a-f]+\b|STATE\b.*|Name.*'
To start a stopped instance use the following command.
aws ec2 start-instances --instance-ids the_instance_id
Don't mix up
run-instances the later is to start a new instance from an AMI.