Timer: Interrupt Flag (IF) and Interrupt Enable (IE)

The more I read, the more confusing I become

The problem I am having is when we set. reset interrupt flags, enable bit...

Initialize:
Clear IF
Set IE
Set GIE (must), PEIE (if I use push button)

IRS of Timer:
Save context
Clear GIE (must), PEIE (if I use push button)
Reset Timer
Restore context


Reset Timer:u]
Clear IF
Set IE
Set GIE (must), PEIE (if I use push button)

The routine of timer reset and initialise seem the same. Anyone please help me out.
Thanks