## Discretization

I have trouwble discretisizing the following Non-linear differential equation with stepsize $h=\frac{1}{2}$:

$-y''+y^3=0$ with $y(0)=1, y'(1)=0$

where $y'(1)=0$ is approximated with a second order differential formula.

I'm clueless, I don't quite understand what must be done here. Can someone offer me some guidelines?