On your Ansible controller make sure the sshpass binary exists if Ansible has to connect to target machines via SSH username-password authentication instead of SSH key authentication. The binary usually comes with a package of the same name.

We're assuming that you're running Ansible as a Python package inside a virtual environment. Install Ansible like so:

pip install ansible

We're also assuming that secrets are stored in a HashiCorp Vault instance to which you have access. These role access Vault via hvac, the HashiCorp Vault API client for Python 3.x, see github.com/hvac/hvac for reference. Install it like so:

pip install hvac

Vars

For Vault access copy ansible/roles/20-common-20-ssh/defaults/main.yml.example to a proper ansible/roles/20-common-20-ssh/defaults/main.yml and set Vault credentials and locations as needed.
Create your inventory, copy ansible/hosts.yml.example into a proper ansible/hosts.yml file with at least one host in host group all.
Replace ansible/group_vars/all/vars.yml.example with a proper ansible/group_vars/all/vars.yml file and set at least ansible_user. It defaults to ansible_user: 'root'.
In ansible/roles/20-common-20-ssh/files/root/.ssh copy both authorized_keys.example and known_hosts.example to proper files. They contain SSH authorized_keys and public SSH host keys you want installed on target machines.

Run it

On first run execute it like so:

ansible-playbook --tags 'first_run' --inventory hosts.yml playbook.yml

The first_run tag ensures that ansible_password variable gets set which in turn causes Ansible to log in to target machines via SSH username-password authentication.

On subsequent runs like so:

ansible-playbook --inventory hosts.yml playbook.yml