Were you building from a Dockerfile or Containerfile? If so, you don't need to use buildah you can just use podman build, same as you would docker. So to build an image from a Dockerfile/Containerfile in the current directory just run

podman build -t what_the_image_to_be_tagged .

Then to reference the container by name when you run it, you gotta specify that at runtime:

podman run --name foo the_image_you_just_tagged