Add a Toasters.Model to your model.

type alias MyModel =
    { toasters : Toasters.Model
    }

Add a Toasters.Model to your model.

myInitialModel : MyModel
myInitialModel =
    { toasters = Toasters.init
    }

Add a Toasters.Msg to your Msg.

type MyMsg
    = ToastersMsg Toasters.Msg

Use in your update function.

myUpdate : Msg -> Model -> (Model, Cmd Msg)
myUpdate msg model =
    case msg of
        ToastersMsg toastersMsg ->
            { model | toasters = Toasters.update toastersMsg model.toasters } ! []

Add to your subscription function.

subscriptions : Model -> Sub Msg
subscriptions model =
    Sub.batch
        [ Toasters.subscription model.toasters |> Sub.map Msg.ToastersMsg
        ]

Add to your subscription function.

myUpdate : Msg -> Model -> (Model, Cmd Msg)
myUpdate msg model =
    case msg of
        SavedSuccessfully ->
            { model
                | isSaving = False
                , toasters = Toasters.addGreen "Data saved Successfully :)" model.toasters
            } ! []

Add to your subscription function.

myUpdate : Msg -> Model -> (Model, Cmd Msg)
myUpdate msg model =
    case msg of
        SavingFailed ->
            { model
                | isSaving = False
                , toasters = Toasters.addRed "Data could not be saved :(" model.toasters
            } ! []

Add to your view function.

div
    []
    [ Toasters.view model.toasters
        |> Html.map ToastersMsg
    , div
        []
        [ text "My Cool App" ]
    ]