docs: update readme

README.md

@@ -11,6 +11,70 @@
 
 This fork is a rewrite to use Google's HTTP v1 API.
 
+
+# Getting started
+
+## Installation
+
+Add the following to your `Cargo.toml` file:
+
+```toml
+[dependencies]
+fcm = { git = "https://github.com/rj76/fcm-rust.git" }
+```
+
+Then, you need to add the credentials described in the [Credentials](#credentials) to a `.env` file at the root of your project.
+
+## Usage
+
+For a complete usage example, you may check the [Examples](#examples) section.
+
+### Import
+
+```rust
+use fcm;
+```
+
+### Create a client instance
+
+```rust
+let client = fcm::Client::new();
+```
+
+### Construct a message
+
+```rust
+let message = fcm::Message {
+    data: None,
+    notification: Some(Notification {
+        title: Some("I'm high".to_string()),
+        body: Some(format!("it's {}", chrono::Utc::now())),
+        ..Default::default()
+    }),
+    target: Target::Token(device_token),
+    fcm_options: Some(FcmOptions {
+        analytics_label: "analytics_label".to_string(),
+    }),
+    android: Some(AndroidConfig {
+        priority: Some(fcm::AndroidMessagePriority::High),
+        notification: Some(AndroidNotification {
+            title: Some("I'm Android high".to_string()),
+            body: Some(format!("Hi Android, it's {}", chrono::Utc::now())),
+            ..Default::default()
+        }),
+        ..Default::default()
+    }),
+    apns: Some(ApnsConfig { ..Default::default() }),
+    webpush: Some(WebpushConfig { ..Default::default() }),
+}
+```
+
+### Send the message
+
+```rust
+let response = client.send(message).await?;
+```
+
 # Credentials
 
 This library expects the Google credentials JSON location to be 
@@ -19,4 +83,13 @@ Please follow the instructions in the [Firebase Documentation](https://firebase.
 
 ## Examples
 
-Check out the examples directory for a simple sender.
+For a complete usage example, you may check out the [`simple_sender`](examples/simple_sender.rs) example.
+
+To run the example, first of all clone the [`.env.example`](.env.example) file to `.env` and fill in the required values.
+
+You can find info about the required credentials in the [Credentials](#credentials) section.
+
+Then run the example with `cargo run --example simple_sender -- -t <device_token>`
+
+
+