This is probably the most straightforward way of creating states. First, you create an enum with all your states:

pub enum MyState {
    State1,
    State2,
    State3,
    StateWithData(String),
}

Next, you need to import your argument, error and event types:

use some_module::{Argument, Event, Error};

And then you can finally implement State:

use machinae::{State, Trans};

impl State<Argument, Error, Event> for MyState {}

Then, you'll have to match the enum in every method:

fn start(&mut self, arg: Argument) -> Result<Trans<Self>, Error> {
    match *self {
        State1 => Trans::None,
        State2 => Trans::None,
        State3 => Trans::None,
        StateWithData(_) => Trans::None,
    }
}