Menu2: documentation?

Heyho,

is there a complete documentation about menu2?

I tried the code examples from here and here but neither works for me since I am getting an error message:

Undefined symbol ':MyMenuDelegate' detected

Well, fine, sure. I am missing something. But the sites I linked above aren't helpful-

There're samples in the sdk's folder but they aren't helpful either and copying some code without understanding the logic is kinda like trial and error.

I am trying to create a menu for my watch face that offers a few customizing options. Kinda like this:

main menu

dial
    - size
        - option 1
        - option 2
        - option 3
    
    - color
        - option 1
        - option 2

data fields
    - top
    - left
    - right
    
language
    - english
    - german