Travel the path of a Padawan.
Star Wars Jedi: Fallen Order features eight different lightsaber colors, but only two are unlocked at the beginning. In order to find the rest, you'll need to work your way through a significant chunk of the story first. They aren't missable and are related to a story mission on the planet Ilum, which you cannot access right away. Once you can get to Ilum, though, finding your kyber crystal is a breeze.
Full story from the WindowsCentral blog...