I have been learning from this book Fabio Alessandro Locati, published under Packt>.

There is one simple exercise where there is an example of “Ensuring that NTP is installed, configured and running”. The codes can be found at https://github.com/PacktPublishing/Learning-Ansible-2.X-Third-Edition/tree/master/Chapter02

--- 
- hosts: all 
  remote_user: ansible
  tasks: 
    - name: Ensure NTP is installed 
      yum: 
        name: ntp 
        state: present 
      become: True 
    - name: Ensure the timezone is set to UTC 
      file: 
        src: /usr/share/zoneinfo/GMT 
        dest: /etc/localtime 
        state: link 
      become: True 
    - name: Ensure the NTP service is running and enabled 
      service: 
        name: ntpd 
        state: started 
        enabled: True 
      become: True