Trying to get my head around the trustedFunction method

I don't really understand where a script with trustedFunction method goes. Is it supposed to go in the JavaScript folder?

It has to go in an application folder, either the Acrobat application or the user's application folder for Acrobat.

You can use the "app.getPath('app', 'javascript');" for the application folder location and "app.getPath('user', 'javascript');" to get the user application folder. You will have to use those commands in the JavaScript debugger.

I hope I am reading your question correctly. You might want to break the problem into two parts: Creating trusted functions and the creating the button functions you want.

First, create a JS file in the app JS folder (for global access) or user JS folder (for single user access) as mentioned by gkaiseril. In this JS file, create a trusted function for each of the functions you need. For Example, create the file StevenDTrustedFunctions.JS containing your trusted functions, such as:

trustedCreateTemplate = app.trustedFunction( function (param1, param2)
{
// Additional code may appear above
app.beginPriv(); // Explicitly raise privilege
// insert your template creation code here that needs preivileged execute
app.endPriv();
// Additional code may appear below.
})

You may wish to create several trusted functions each covering a separate code segment needing a raised execution privilege, such as app.newDoc(), doc.saveAs(), etc.

Second, in your code for your toolbar button, you can now reference each trusted function. For example, if your trustedCreateTemplate returned an object, then in your button code you could use code such as:

var myTemplate = trustedCreateTemplate( var1, var2 ); // assuming you need 2 variables.

Additionally, if your toolbar button code is JS and is also placed in the same folder as the trusted function code, then both the button code and the trusted function code can reside in the same file.

Also remember that if you use any function which is not a part of the app object, you will need to pass the parent object as a parameter as well.
For example, if you want to create a trusted function for doc.saveAs(), you can't use the "this" keyword. You need to pass doc itself as a parameter to your trusted function (as well as the new path, and any other parameters you might need).