How to create a bullet?

Hello,
I’m new in Unity, so I’m making small games to get more practice.
Now I have this (trivial?) problem:

I have a cannon, and I need to create a bullet (a prefab) when the player press “fire”. In my mind I created a bullet in prefab, then I wanted to instantiate it when player fires a bullet. But it seems I need to make an instance in the game, else I cannot access (unless I use Resources) to the bullet prefab. It does not seem the right way.
So, please can you suggest me how to dynamically create a bullet at runtime when the player hit “fire”?
Do I need to put a bullet instance in the game (and “disable” or make it not visible?)?

Thank you for your help!

You’d better keep that function in mind !

But in order to use that function (I tried it) I need to create an instance of the object in the game (then I can “clone” it as many times I want).

EDIT: it means an object instance must already exist.

Yea, you could create a bullet as a prefab object set it up how you want it to look size, texture…etc then you can call it with Instantiate…

copy this for the cannon in java script it works heres some scripts
401803–13808–$GUI Style Script.js (323 Bytes)401803–13809–$killmeovertime.js (83 Bytes)401803–13810–$textcontroll.js (418 Bytes)401803–13811–$turrent colision.js (259 Bytes)401803–13812–$healthcontroll.js (821 Bytes)

Ok, I red your suggestions and the official manual (read again and again!).
I understood that I need to create a var … and using DRAG-DROP I can “attach” the prefab that will be instanced.

Thank you for the help!