Employee Indiscipline - how to stop this indiscipline nature of employees?

In my company I am the first HR person they are not used to this post and what are the duties of an HR. I need your help i some implementations of policies and another topics.
1. No body follows policy rules even when I took any decision for it my directors.
2. Many a time I circulate the notices about late coming early going but everyone has their own excuses. Please help me to make a general policy and how to stop this indiscipline nature of employees.
3. They are also used to take leaves on same day just put messages in office whats app group and my directors are shouted on me about this but nobody is cooperate to follow.
Please suggest me.

How long have you been working there?
First thing get familiar with the office, departments and people working there.
All this indiscipline can be noted down and discussed with Directors/HR head and then their support enlisted.
Directors/MD/CEO has to be on board for ensuring change from old habits.
Frame out a policy in accordance with company needs and labour laws applicable to your setup.
On approval from top management, then let the environment know of the policy by informing the HoDs through HR boss.
Violations can be brought to notice of HOD
They can decide whether late coming, early departure is affecting discipline, production,output.As HR singlehandedly you cannot control all these events.