Edit README file

README.md

@@ -8,6 +8,28 @@ further developed depending on user's preference.
 > This package will be merged into main branch s.t. `impedance_controller` (meta)package
 > to include this package as a (sub)package
 
+for example,
+```
+.impedance_controller
+|- assets
+    |- data
+    |- model
+|- common
+    |- controller
+    |- math
+    |- motion
+    |- robot
+    |- utilities
+|- dob_impedance_controller
+|- ros1_mujoco_interface
+|- test
+|- .clang-format
+|- .gitignore
+|- flake.lock
+|- flake.nix
+|- README.md
+```
+
 ## Package Structure
 ```txt
 .ros1_mujoco_interface