This may sound silly, but how do you learn new skills.

I put points in some constellations (Dryad, and Turtle), and the last star
gives me an option of several skills, but they are in red, and says “Skill Not Learned.”

Sorry if this is a simplistic question; I did look at the game guide but there’s really no answer to this question.

Thanks for any help.

What you are looking at is the list of skills that a celestial power can be bound to. If you don’t have any of the skills in that list unlocked, then you cannot bind the celestial power to them.

You need to put at least one skill point into any of those skills, on your main class training screens.