Shoot arrow in the sky? force/vector I don't know problem im a beginner

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.

2 examples of what I want:

Look at the arrow-turrets, that kind of shooting is what I want.

I painted a quick sketch.

 

Hi I am a beginner too... i think your problem especially you want it on detailed.. will not be answered.. your asking actually an entire code. I think you should study about the transform.position Vector3.up and Vector3.down and find out for yourself. I read this on Unity Wiki that this kind of questions are most likely not be answered. I think you read tutorials about it.