On page 49 (Building an AMI with Packer), I was not able to run the packer build ami_build.json command. Apparently the amazon plugin needed to be installed first, by running this command: packer plugins install github.com/hashicorp/amazon
After that, I was able to run the packer build command, but it did not complete because the ami name in the filters section of the ami_build.json file is not valid.
I went looking for valid ami names and found this one, which allowed me to run the script: al2023-ami-2023.6.20241121.0-kernel-6.1-x86_64
I hope this helps other people in the future!