Revise readme

Readme.txt

@@ -1,17 +1,19 @@
-  References for Freenove Ultimate Starter Kit for Arduino
+  Freenove Ultimate Starter Kit for Arduino
 
-References
-  The references for this product includes the following folders and files:
-    Datasheet	    Datasheet for electronic components and modules
-    Libraries	    Libraries for Arduino sketches
+How to download
+  Please click the green "Clone or download" button, then click "Download ZIP" button in the pop-up window to download the zip file that contains all these files. Clicking the "Open in Desktop" button will lead you to install Github software instead of downloading these files. 
+  If you have any difficulties, please send email to our support for help.
+
+Files
+  The files for this product and their introduction are as follows:
+    Datasheet       Datasheet for electronic components and modules
+    Libraries       Libraries for Arduino sketches
+    Sketches        Sketches for Arduino projects
     Processing      Sketches for Interacting with Processing projects
-    Sketches	    Sketches for Arduino projects
-    Readme.txt	    Instructions
-    Tutorial.pdf    Tutorial for Arduino
+    Readme.txt      Instructions
+    Tutorial.pdf    Tutorial for learning Arduino
     Processing.pdf  Tutorial for Interacting with Processing
 
-  You can click the green Clone or download button in this page, then click Download ZIP to get all these files in zip format. If you have any difficulties, you can send email to our support for help.
-
 Support
   Freenove provides free and quick technical support, including but not limited to:
     Quality problems of products
@@ -25,7 +27,7 @@ Support
   On working day, we usually reply to you within 24 hours.
 
 Copyright
-  Freenove reserves all rights to the book. No copies or plagiarizations are allowed for the purpose of commercial use. 
+  Freenove reserves all rights to the files for this product. No copies or plagiarizations are allowed for the purpose of commercial use. 
   The code and circuit involved in this product are released as Creative Commons Attribution ShareAlike 3.0 (http://creativecommons.org/licenses/by-sa/3.0/legalcode). This means you can use them on your own derived works, in part or completely, as long as you also adopt the same license. 
   Freenove brand and Freenove logo are copyright of Freenove Creative Technology Co., Ltd and cannot be used without formal permission.