macOS is Unix underneath, so your Mac already has a shell and most of what this class needs. You just need a good terminal and a package manager.
The built-in Terminal app works, but
iTerm2 is nicer. Download
it, drag it to Applications, and open it. You should see a
prompt ending in %. That is your shell.
Homebrew is the standard package manager for the Mac. Follow the one-line install command on its home page, and let it install the Xcode command line tools if it asks (that also gives you git).
Then install the small tools the lab uses:
brew install git
That is the pattern for anything else you ever need:
brew install <name>. The xxd
and nano commands used in the lab are already on
your Mac.
Copy the exact error message and ask Claude (or paste it into claude.ai until you have Claude Code installed). Homebrew problems are common and almost always quickly solved.