Unless you spend LOTS of time...
...I think there's 2 things you won't learn without an instructor.
One is RT
The other is the whizz wheel
It's possible to crank through the Nav book and pick it all up but I think it would take for ever.
Now I've got the PPL I do most of my calcs on a calculator. I stil maintain that the whizz wheel doesn't really have the precision you need to get the accuracy that the exams require.
Get ready for a LOT of long division & long multiplication!