Add description to readme

README.md

@@ -1,2 +1,14 @@
 # s2e-user-example
-An example of S2E user side repository.
+An example of S2E user side repository.  
+This repository provides the following samples.
+- A sample code to make S2E user side repository using `git submodule`.
+- Sample codes for tutorials in [s2e-documents](https://github.com/ut-issl/s2e-documents).
+
+# Branches
+- `main` branch
+  - This is the simplest `s2e-user` repository.
+  - This branch is a sample code for [How To Make New Simulation Scenario](https://github.com/ut-issl/s2e-documents/blob/develop/Tutorials/HowToMakeNewSimulationScenario.md) in the `s2e-documents`.
+  - Users can refer this branch to make their `s2e-user`.
+- `sample/hoge` branches
+  - Sample codes for tutorials in [s2e-documents](https://github.com/ut-issl/s2e-documents).
+  - The branch name is same with the tutorial titles.