>>13819471Start with your uni's PCHEM offerings, and check their course catalog to see if they offer any kind of theoretical/computational courses. If they don't your stuck ordering either Jensen or Cramer's computational chemistry intros followed by a classic like szabo and ostlund, or trying to wade through the fucking morass of modern computational introductions, half of which are useless, the other half too dense for your average undergraduate.
Get good at doing integrals/PDEs or at the minimum understand them and pickup C++ or Fortran if you can't cut it at the whiteboard