Add basic usage to the readme file.

README.md

@@ -1,7 +1,47 @@
 # HiddenCamera
 A library that allows you to take picture secretly, in the background without alerting users.
 [![Build Status](https://travis-ci.org/CottaCush/HiddenCam.svg?branch=master)](https://travis-ci.org/CottaCush/HiddenCam)
-##
+
+## Gradle Dependency
+
+Add the dependency to your app's `build.gradle`:
+
+```groovy
+implementation 'com.cottacush:HiddenCamera:0.0.1'
+```
+
+## Usage
+
+It is very easy to get started with Hidden cam. 
+First, initialize the camera engine with a `Context`, A `File` that 
+represents the base storage folder where the captured images will be saved to, 
+and an `OnImageCapturedListener` to get the capture results:
+
+```kotlin
+   val hiddenCam = HiddenCam(context, baseStorageFolder, captureListener)
+```
+Then prepare the camera for capturing by calling the `start()` method:
+
+```kotlin
+    hiddenCam.start()
+```
+You can now start capturing images with:
+```kotlin
+    hiddenCam.captureImage()
+```
+When you are no longer actively capturing images, stop the camera engine to free the camera hardware by calling:
+
+```kotlin
+    hiddenCam.stop()
+```
+Finally, to clean up call
+
+```kotlin
+    hiddenCam.destroy()
+```
+
+That's all for basic setup. The captured images should be save at the storage folder provided.
+
 
 ##  License