While the full book isn't there, many of the foundational papers cited within are available for free.
Finding the PDF is only step one. This is not a casual read. Here is a study strategy: schoen yau lectures on differential geometry pdf
This is where the "analysis" begins in earnest. The authors explore the Laplace-Beltrami operator, proving maximum principles, eigenvalue estimates, and the existence of harmonic functions on manifolds. The famous Yau's gradient estimate for harmonic functions is presented in a clear, methodical way. While the full book isn't there, many of