How to save as prefab when a button is pressed

Hello, I found this Thread but I did not found a good answer. I would like to create a button and if this button is pressed it should save the 2D created Character (<- 'Character' is an Empty GameObject with child Objects attached on it, like 'Arms', 'Legs', etc. and those have a spriteRenderer on them to select the different sprites) with all of its child objects as a prefab.

I have something like this:

 public void SaveCharacterAsPrefab() 
     {
         Transform.Instantiate Character
         int Character
         string prefabPath = "SavedCharacters";
         PrefabUtility.CreatePrefab("Assets/Resources/" + prefabPath + "/" + Character.name + ".prefab", Character, ReplacePrefabOptions.ReplaceNameBased);
     }

But (of course) it doesn't work because I don't know exactly how to 'tell the script' that it should save the Character with all of its child objects and (for example) name/save it as 'Character 1'. I don't know how I can solve it... Thanks for anyone who wants to help!