diff --git a/docs/ecolyo/functionalities/challenge.md b/docs/ecolyo/functionalities/challenge.md
index 2cf4828cc8193561d1d7b006f4c3768552ec70c9..ddc2e65f6961327141fed52928aafcd3998d8097 100644
--- a/docs/ecolyo/functionalities/challenge.md
+++ b/docs/ecolyo/functionalities/challenge.md
@@ -5,6 +5,26 @@ This section explain all the functionnalities in the challenge part
 
 ## Quiz
 
+### Basic Question
+
+All basics Questions are created in the quizEntity.json. We have to add :
+- questionLabel => Label of the question
+- Answers => An array of three answers (answerLabel, isTrue)
+- description => Explain the question
+- source => Source of the explanaition
+
+In the question page the user have to select an answer and click validate. 
+Then, he sees the right answer and a modal with the explaination and the source. After this modal, he goes to the next question.
+
+### Custom Question
+
+At the end of every quiz, we're creating a custom question. During the creation of the quiz, we have to add :
+- type => data or calculation
+- period => the period selected for the calcul
+- timestep => the interval of the calcul (Day, Month, Year)
+We get all this information to determine the custom question (All information are in the quizEntity.json). Depending of the question type, the system calcul a maximum or an average data. 
+Then, he generate two randoms answers following the right answer. 
+
 ## Mission
 
 ## Duel
@@ -13,7 +33,8 @@ This section explain all the functionnalities in the challenge part
 
   In order to find a valid reference period we search for a period which is defined by the duel duration.  
   We check the most recent period first if it's complete and then we go farther and farther in the time if the ones before got missing values.  
-  We also define a threshold for a maximum old period (6 months for the moment). If the thresold is reached and no valid period was found, we alert the user that he can't lunch the duel and have to wait before he can retry this process.
+  We also define a threshold for a maximum old period (6 months for the moment determined in the code ==> hardcoding).
+  If the thresold is reached and no valid period was found, we alert the user that he can't launch the duel and have to wait before he can retry this process.
 
 ### On going