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.
23rd January 2019 From India, Pune