I'm slightly befuddled by is what it means when I'm asked to

Draw the Feynman diagram in momentum space for the two point function of $\frac{\lambda}{3!}\phi^3$ theory for order $O(\lambda^2).$

I can draw Feynman diagrams, and I thought two-point function meant

$$\langle0\|\phi(x)\phi(y)\|0\rangle$$

and what I know about $ O(\lambda^2)$ is that it will have more diagrams than $ O(\lambda).$

Other than that, I'm a bit lost. I mean, I'm not even sure if this is a really simple calculation or quite a long one.

Apologies to myself if anything I've written above is embarrassing.