We learn about the tetrahedral geometry of methane because the same tetrahedral geometry is important in many other molecules. sp3 systems are very common and many have handedness or are chiral. You need to master drawing interconnected tetrahedrons for larger molecules and to draw this handedness efficiently. In this example, we will draw (S)-butan-2-ol. Don't worry if you don't know what this molecule is or understand its name yet...we will learn this soon enough.