Find the number of ways to move along the grid from $(0,0)$ to $(n,n)$ such that one is always in the region $x \geq y$.

Question

Here is the Question :-

Find the number of ways to move along the grid from $(0,0)$ to $(n,n)$ such that one is always in the region $x \geq y$.

First of all , I kind of couldn't understand the part which meant the region $x \geq y$ , and the answer is given as the nth Catalan number $C_n$ . But I couldn't understand why and how .

Any hints or explanations to this Question will be greatly appreciated !!