Dockerfile.lb not found

[Enigamict]

I typed the following commands, and got errors,
sudo docker buildx build --push --platform linux/arm64,linux/amd64 --tag lizrice/ubuntu-ebpf-lb -f Dockerfile.lb .

error: failed to solve: failed to read dockerfile: open /tmp/buildkit-mount4127635099/Dockerfile.lb: no such file or directory

Where do I get the files from?

[Enigamict]

Thank you for your response!