SSH may be installed on the pi but may need to be enabled. That was the second to last bullet point in the requirements. The final on being to install Ansible. If you did not get the requirements taken care of, installation will not be successful.
Please first try to SSH into your pi. Once you have that done, you should install Ansible. After that, you should be able to run the playbook from step 7 and we can proceed from there.
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