diff --git a/doc/kotlin-coding-guideline.md b/doc/kotlin-coding-guideline.md
index ec2f70c..13979fa 100644
--- a/doc/kotlin-coding-guideline.md
+++ b/doc/kotlin-coding-guideline.md
@@ -1,3 +1,22 @@
+# Kotlin Coding Guidelines
+
+## Code structure
+
+- short methods (not too long)
+  - add suggestion how to refactor
+
+- only one level of abstraction
+  keep only one abstraction level in method  
+
+- keep low level of identation
+  less is more 
+  for example when() if-else if-else is not very good redable
+
+- use variable for expression / condition
+
+
+## Questions
+
 ### `value.?let` or `if (value != null)`
 
 Is really better to use
@@ -24,4 +43,3 @@ val value = object : Type {
     // implementation
 }
 ```
-