Add a very basic explanation

To get started.

README.md

@@ -3,3 +3,177 @@
 ViewController's for SwiftUI.
 
 WIP.
+
+The core idea is that the `ViewController` is owning, or at least driving,
+the View(s). Not the other way around.
+
+
+## How to Use
+
+More details will be posted but to get started.
+
+### Step A: Setup Project and Root VC
+
+- create a SwiftUI project in Xcode (iOS is tested better)
+- add the `ViewController` package, 
+  e.g. via `[email protected]:ZeeZide/ViewController.git`
+- create a new RootViewController, e.g. `HomePage.swift`:
+  ```swift
+  import ViewController
+
+  class HomePage: ViewController {
+
+    struct ContentView: View {
+
+      var body: some View {
+        VStack {
+          Text("Welcome to MWC!")
+            .font(.title)
+            .padding()
+
+          Spacer()
+        }
+      }
+    }
+  }
+  ```
+- Instantiate that in the scene view, the `ContentView.swift`
+  generated by Xcode:
+  ```swift
+  import ViewController
+
+  struct ContentView: View {
+    var body: some View {
+      MainViewController(HomePage())
+    }
+  }
+  ```
+- Compile and Run, should show the HomePage
+
+### Step B: Add a presented VC and navigate to it
+
+- create a new ViewController, e.g. `Settings.swift`:
+  ```swift
+  import ViewController
+
+  class Settings: ViewController {
+
+    struct ContentView: View {
+
+      var body: some View {
+        VStack {
+          Text("Welcome to Settings!")
+            .font(.title)
+            .padding()
+
+          Spacer()
+        }
+      }
+    }
+  }
+  ```
+- Add an action to present the `Settings` from the `HomePage`:
+  ```swift
+  import ViewController
+
+  class HomePage: ViewController {
+
+    func configureApp() {
+      show(Settings()) // or `present(Settings())`
+    }
+
+    struct ContentView: View {
+
+      @EnvironmentObject private var viewController : HomePage
+
+      var body: some View {
+        VStack {
+          Text("Welcome to MWC!")
+            .font(.title)
+            .padding()
+
+          Divider()
+
+          Button(action: viewController.configureApp) {
+            Label("Configure", systemImage: "gear")
+          }
+
+          Spacer()
+        }
+      }
+    }
+  }
+  ```
+
+Pressing the button should show the settings in a sheet.
+
+
+### Step C: Add a NavigationController for Navigation :-)
+
+- Wrap the HomePage in a `NavigationController`, in the scene view:
+  ```swift
+  import ViewController
+
+  struct ContentView: View {
+    var body: some View {
+      MainViewController(NavigationController(rootViewController: HomePage()))
+    }
+  }
+  ```
+
+Note pressing the button does a navigation. Things like this should also
+work:
+```swift
+func presentInSheet() {
+  let vc = SettingsPage()
+  vc.modalPresentationStyle = .sheet
+  present(vc)
+}
+```
+
+
+### Adding a `PushLink`
+
+The presentations so far make use of a hidden link. To explicitly
+inline a `NavigationLink`, use `PushLink`, which wraps that.
+
+- Add a `PushLink` (until I get an `NavigationLink` init extension working)
+  to present the `Settings` from the `HomePage`:
+  ```swift
+  import ViewController
+
+  class HomePage: ViewController {
+
+    struct ContentView: View {
+
+      var body: some View {
+        VStack {
+          Text("Welcome to MWC!")
+            .font(.title)
+            .padding()
+
+          Divider()
+
+          PushLink("Open Settings", to: Settings())
+
+          Spacer()
+        }
+      }
+    }
+  }
+  ```
+
+
+### Who
+
+ViewController is brought to you by [ZeeZide](https://zeezide.de).
+We like feedback, GitHub stars, cool contract work, 
+presumably any form of praise you can think of.
+
+**Want to support my work**?
+Buy an app:
+[Past for iChat](https://apps.apple.com/us/app/past-for-ichat/id1554897185),
+[SVG Shaper](https://apps.apple.com/us/app/svg-shaper-for-swiftui/id1566140414),
+[Shrugs](https://shrugs.app/),
+[HMScriptEditor](https://apps.apple.com/us/app/hmscripteditor/id1483239744).
+You don't have to use it! 😀