I would highly recommend getting
Bowditch's book , with it you will learn navigation. It is not cheap but it is the bible for open ocean navigation. I read some of it while I was qualifing to be a Quartemaster in the Navy.
I have a fair amount of experience with celestial navigation, only I cheated and had an electronic navigator. It was a celestial based inertial dead reconing gyroscopic navigation system :grin: that would keep position to within a few feet per month.
Good luck and remember practice, practice, practice.
MM