Construct a cubic spline for equally spaced nodes.

Question

I understand what a cubic spline is, but our professor likes to give us graduate level assignments for our undergraduate class. So, im given $f(x) = \frac{1}{1+x^2}$, Let $-5 = x_0 < x_1 < ... < x_n = 5$ be $(n+1)$ equally spaced nodes on $[-5.5]$ for $n = 5, n = 10$ construct cubic splines for both values of $n$. I dont understand how to get equally spaced nodes, what is the formula for this? And how do i make cubic splines from there. All the notes from class just ask to construct a cubic spline through the following values. Which i can do. But not this.