Turret shooting arrows?

Hey thanks in advance, I’m really struggling with this.

Before we start, I should let you know this is in 3D not 2D,
I’m trying out a little tower defense project and I want a turret that can shoot arrows; I found a tutorial how to get a bullet to shoot to the target but that’s not what I’m aiming for.
This arrow has to first fly up in the sky and then decrease down to the ground/target. because nobody shoots arrow in a straight line like a gun.

If someone could help me that would be great, if you can please explain in detail what I should do, if I see the code I will understand it but the documentation won’t help me at all right now.

(Im working in JavaScript)

So the whole trajectory of the arrow is visible to the camera? I’m making some other assumptions about the game’s nature here, too, but here we go:

Before firing, you must know either where the arrow will land, or which target it will hit. The first approach may include a step for compensating for the intended target’s velocity, also known as “leading a shot”. The second approach would gradually correct the arrow’s path (over time, while in flight) to ensure the chosen target is hit.

From there, the math is fairly simple: http://www.physicsclassroom.com/class/1DKin/Lesson-6/Kinematic-Equations