To graph the equation $y = -2$, follow these steps:

1. Identify the y-intercept: The equation $y = -2$ means that for any value of $x$, the value of $y$ is always $-2$. This tells us that the line crosses the y-axis at the point $(0, -2)$.

2. Plot the y-intercept: Start by plotting the point $(0, -2)$ on the Cartesian coordinate plane. This is the point where the line will intersect the y-axis.

3. Draw a horizontal line: Since the equation $y = -2$ represents a horizontal line, draw a straight line through the point $(0, -2)$ that extends infinitely in both directions parallel to the x-axis