diff --git a/README.md b/README.md
index 67291f7..037f78d 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,25 @@ to install the full package.
 
 Installing a single component is currently not supported.
 
+## Target
+
+1. TextRenderer translate the string from Terminal to a bitmap array.
+   the bitmap will output in the terminal and store in shared memory.
+
+## How to use the program
+
+1. You must install catch2 in your computer.
+     the catch2 website is https://github.com/catchorg/Catch2
+     
+     If you cannot install Catch2 from a package manager (e.g. Ubuntu 16.04 provides catch only in version 1.2.0) 
+     you might want to install it from the repository instead. Assuming you have enough rights, you can just 
+     install it to the default location, like so:
+     ~~~~
+     $ git clone https://github.com/catchorg/Catch2.git
+     $ cd Catch2
+     $ cmake -Bbuild -H. -DBUILD_TESTING=OFF
+     $ sudo cmake --build build/ --target install
+ 
+2. Debug
+
+