diff --git a/README.md b/README.md
index 67291f7..cdadfe7 100644
--- a/README.md
+++ b/README.md
@@ -7,3 +7,35 @@ to install the full package.
 
 Installing a single component is currently not supported.
 
+## Target
+
+TextRender build exports an interface target TextRender::TextRender. 
+
+This means that if TextRender has been installed on the Project Path, it 
+should be enough to do.
+
+translate a string from terminal to the readable form of shared memory . 
+
+## Usage
+
+    mkdir build
+    cd build
+    cmake ..
+    make
+
+## Description
+
+TextRender has two class, Bitmap class and Font class. 
+
+res/font.bmp (bitmap data, used by Bitmap::load() function)
+
+res/font.toml (configuration file, it configure how to read the font.bmp)
+
+src/Bitmap class, it used to read the font.bmp file.
+
+src/Font class, it read the font.bmp data by Bitmap class, 
+translate a string to a bitmap.
+
+test folder used to test.
+
+main folder is only used to test now.
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