I'm having trouble understanding point (30) on page- 155 of Visual Complex Analysis, the following is given:
Let $C$ be the unique circle through the points $q,r,s$ in the z-plane, oriented so that these points succeed one another in the stated order. Likewise, let $\tilde{C}$ be the unique oriented circle through $\tilde{q} , \tilde{r}, \tilde{s}$ in the $w$-plane. Then the Moebius transofrmation given by (29) maps $C$ to $ \tilde{C}$ , and it maps the region lying to the left of $C$ to the region lying left of $\tilde{C}$
In the above paragraph, what is exactly meant by something being a left of a circle?


It means the dark region whose boundary is the circle.
Imagine you are walking along the circle in the direction indicated by the arrow. Then the region is on your left. On the left figure, the region is the bounded open disk; on the right one, the region is the outside part of the circle.