Remove the App.Button module (only served as an example).

src/App/Button.purs

@@ -1,34 +0,0 @@
-module App.Button where
-
-import Prelude
-import Halogen as H
-import Halogen.HTML as HH
-import Halogen.HTML.Events as HE
-
-type State
-  = { count :: Int }
-
-data Action
-  = Increment
-
-component :: forall q i o m. H.Component q i o m
-component =
-  H.mkComponent
-    { initialState: \_ -> { count: 0 }
-    , render
-    , eval: H.mkEval H.defaultEval { handleAction = handleAction }
-    }
-
-render :: forall cs m. State -> H.ComponentHTML Action cs m
-render state =
-  HH.div_
-    [ HH.p_
-        [ HH.text $ "You clicked " <> show state.count <> " times" ]
-    , HH.button
-        [ HE.onClick \_ -> Increment ]
-        [ HH.text "Click me" ]
-    ]
-
-handleAction :: forall cs o m. Action → H.HalogenM State Action cs o m Unit
-handleAction = case _ of
-  Increment -> H.modify_ \st -> st { count = st.count + 1 }