Universe is a puzzle.  Rotating opens the ways or doors between locations.  Like those who can master a Rubicks cube, there are those that can see/find the doors.
Astronomy is key to knowing timing.
Sun signs give clues
Ancient civilizations give clues
Some doors might flare.  Deadly to go through as it leads to a star.  Circumstances lead to stable door.

Stars as a map.

References in Earth's history.
  Peter Pan 1902, "second star on the right and on until morning."
  Stonehenge to measure stars
  Aztec pyramids
  Mayan calendar
  Piri Reis map - documented a time Antarctica wasn't frozen
  Bermuda Triangle

How to move between places?
  Do you need a ritual?  Certain blood?  Just timing?  Stars used to determine conjunctions.
  Who can travel?
  How often?
    Major - Many openings between places
    Minor - Occasional openings
    Outlying - Rare - used as prison
Time?
  Is Time travel a thing?

With the knowledge, anyone can travel.