diff --git a/QSoft.MediaCapture/WebCam_MF.cs b/QSoft.MediaCapture/WebCam_MF.cs
index 740c658..073ac6a 100644
--- a/QSoft.MediaCapture/WebCam_MF.cs
+++ b/QSoft.MediaCapture/WebCam_MF.cs
@@ -5,6 +5,8 @@
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 
+//https://learn.microsoft.com/zh-tw/windows/win32/api/mfidl/nn-mfidl-imfcameraconfigurationmanager
+
 namespace QSoft.MediaCapture
 {
     public sealed class WebCam_MF: IMFCaptureEngineOnEventCallback,IDisposable
diff --git a/README.md b/README.md
index b6e3111..ee1db3e 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,30 @@
-# QSoft.MediaCapture
-https://learn.microsoft.com/zh-tw/windows/win32/api/mfidl/nn-mfidl-imfcameraconfigurationmanager
\ No newline at end of file
+# Quick start
+## Search all video capture
+```c#
+foreach(var oo in QSoft.MediaCapture.WebCam_MF.GetAllWebCams())
+{
+    System.Diagnostics.Trace.WriteLine(oo.FriendName);
+    System.Diagnostics.Trace.WriteLine(oo.SymbolLinkName);
+}
+```
+and filter FriendName, SymbolLinkName get it
+
+# Init and start preview
+```c#
+var camera = QSoft.MediaCapture.WebCam_MF.GetAllWebCams().Find(x => x.FriendName == "USB2.0 HD UVC WebCam");
+if(camera != null)
+{
+    await camera.InitCaptureEngine();
+    await camera.StartPreview(host.Child.Handle);
+}
+```
+try below code when use WPF
+```c#
+var camera = QSoft.MediaCapture.WebCam_MF.GetAllWebCams().Find(x => x.FriendName == "USB2.0 HD UVC WebCam");
+if(camera != null)
+{
+    await camera.InitCaptureEngine();
+    await camera.StartPreview(x => this.image.Source = x);
+}
+
+```
\ No newline at end of file
diff --git a/WpfAppNET472/Window_NET472.xaml.cs b/WpfAppNET472/Window_NET472.xaml.cs
index 77c4177..b48308f 100644
--- a/WpfAppNET472/Window_NET472.xaml.cs
+++ b/WpfAppNET472/Window_NET472.xaml.cs
@@ -31,15 +31,24 @@ public Window_NET472()
         MainUI m_MainUI;
         private async void Window_Loaded(object sender, RoutedEventArgs e)
         {
-            if(m_MainUI == null)
+            if (m_MainUI == null)
             {
                 this.DataContext = this.m_MainUI = new MainUI();
-                foreach(var oo in QSoft.MediaCapture.WebCam_MF.GetAllWebCams())
+                //foreach(var oo in QSoft.MediaCapture.WebCam_MF.GetAllWebCams())
+                //{
+                //    System.Diagnostics.Trace.WriteLine(oo.FriendName);
+                //    System.Diagnostics.Trace.WriteLine(oo.SymbolLinkName);
+                //    //await oo.InitCaptureEngine();
+                //    ////await oo.StartPreview(host.Child.Handle);
+                //    //await oo.StartPreview(x => this.image.Source = x);
+                //    //this.m_MainUI.WebCams.Add(oo);
+                //}
+
+                var camera = QSoft.MediaCapture.WebCam_MF.GetAllWebCams().Find(x => x.FriendName == "USB2.0 HD UVC WebCam");
+                if(camera != null)
                 {
-                    await oo.InitCaptureEngine();
-                    //await oo.StartPreview(host.Child.Handle);
-                    await oo.StartPreview(x => this.image.Source = x);
-                    this.m_MainUI.WebCams.Add(oo);
+                    await camera.InitCaptureEngine();
+                    await camera.StartPreview(host.Child.Handle);
                 }
             }