The Timeline tab will set how the calendar looks in timeline mode.

TimelineScale
Auto adjust timeline for ... when checked will use the default settings if it is unchecked then it will use the settings below it.
# of navigation tiers on top will display how many time displays to show on the top of the timeline
Interval can be set from second to year.
Frequecny is how often an activity is shown.
Format is how the date is displayed

Timeline Options
Disabe drag and drop of activities when checked will not allow the user to drag activities to change their date and time.

See also