Go: Extending unnamed types such as []string

I am a bit confused in regards to type aliases in Go.

I have read this related SO question - Why can I type alias functions and use them without casting?.

As far as I understand, unnamed and named variables are assignable to each other if the underlying structure is the same.

What I am trying to figure out, is can I extend unnamed types by naming them - something like this:

type Stack []string

func (s *Stack) Print() {
    for _, a := range s {
        fmt.Println(a)

    }
}

This gives me the error cannot range over s (type *Stack)
Tried casting it to []string, no go.

I know the below code works - is this the way I should do it? If so, I would love to know why the above is not working, and what is the use of declarations such as type Name []string.

type Stack struct {
    data []string

}

func (s *Stack) Print() {
    for _, a := range s.data {
        fmt.Println(a)
    }
}

Answer

You should dereference the pointer s

type Stack []string

func (s *Stack) Print() {
    for _, a := range *s {
        fmt.Println(a)
    }
}