Talking About The Past

Past simple :
finished actions, past states, past habits and routines, actions following one another

Past perfect :
an event that happened before another past event, an event that happened before a certain point in past

used to + inf :
past habits not repeated anymore, past states not existing any longer

Past continuous :
background description, action in progress at a particular time, action in progress interrupted by another action, two parallel actions

Present perfect :
action that happened at any time up to now, recent past events, past action with results in the present

would + inf :
repeated action in the past