Update the vars as required:
cd examples
PACKER_LOG=1 PACKER_LOG_PATH=packer.log packer build \
-var source_ami=ami-75ebe61f \
-var subnet_id=subnet-7ed32427 \
-var vpc_id=vpc-89388dec \
-var region=us-east-1 \
./packer.aws.json
Update the path below to an existing OVF file:
cd examples
PACKER_LOG=1 PACKER_LOG_PATH=packer.log packer build \
-debug \
-var ovf_source_path=/Users/mfellows/Downloads/output-virtualbox-iso/packer-virtualbox-iso-1417096689.ovf \
./packer.json