andy.js

// index.js

<React.StrictMode>
  <BrowserRouter>
    <App />
  </BrowserRouter>
</React.StrictMode>

// App.js - notice how Home is nested in Layout

<Routes>
  <Route path="/" element={<Layout />}>
    <Route path="/" element={<Home />} />
    <Route path="/foo" element={<Foo />} />
  </Route>
</Routes>

// Layout.js
<>
  <Nav />
  <Outlet />
</>