Fetch out Syllabi of Astrophysics (B.Sc/BS) of some of the Reputed Universities of the World. Follow up with referring each Topic to some of the excellent text books and research papers available for free on Sites like LibGen. Try checking out books on astrophysics on Amazon/Flipkart. For a complete novice or for basic recapitulation, the best book I suppose is Introduction to Astrophysics, by Baidyanath Basu, available cheaply on E Commerce Websites. Besides these, try getting you fundamentals of Physics and Mathematics strong as well as Check out Courses on Astrophysics, Astrobiology, Astronomy and Physics on Coursera/EDx.