In the simplest model, you are working in two dimensions, with the system of equations:
$$\frac{d^2 y}{dt^2} = -g \\\ \frac{d^2 x}{dt^2} = 0 \\\ y(0)=0,y'(0)=\sin(\theta) s \\\ x(0)=0,x'(0)=\cos(\theta) s $$
where $g>0$ is acceleration due to gravity, $\theta$ is the angle of the initial velocity, and $s$ is the initial speed. Note that this model assumes no friction. When you solve you find
$$y(t)=-\frac{1}{2} gt^2 + \sin(\theta) s t \\\ x(t)=\cos(\theta) s t.$$
Now the range of the ball is the horizontal distance it travels before hitting the ground, i.e. the value of $x$ when $y=0$. Can you find this using these equations?