diff --git a/esds.py b/esds.py
index ad08909..148c205 100644
--- a/esds.py
+++ b/esds.py
@@ -195,11 +195,11 @@ class Simulator:
     
     def __init__(self,netmat):
         """
-        Format of netmat: { "interface": {"bandwidth": matrix, "latency": matrix, "is_wired":bool}}
-        For wireless interfaces the diagonal of the bandwidth and latency matrix are very important.
-        It determines the duration of the tranmission for THE SENDER. Thus, at each wireless communication,
-        and addionnal event is created for the sender that corresponds to a send to himself (diagonal of the matrices) used
-        to unlock him from the api.send() call. Consequently, duration of the transmission can be 
+        Format of netmat: { "interface": {"bandwidth": numpy_matrix, "latency": numpy_matrix, "is_wired":bool}}
+        For wireless interfaces the diagonals of the bandwidth and latency matrices are very important.
+        They determine the duration of the tranmission for THE SENDER. It allows to have a different tx duration per node and per interface.
+        Thus, at each wireless communication, an addionnal event is created for the sender that corresponds to a send to himself (diagonals of the matrices) used
+        to unlock him from the api.send() call. Consequently, the duration of the transmission (by the sender) can be 
         different from the time at which the receivers actually receive the data (non-diagonal entries of the matrices).
         """
         self.netmat=netmat
diff --git a/example/simulator.py b/example/simulator.py
index f70c294..aa8df54 100755
--- a/example/simulator.py
+++ b/example/simulator.py
@@ -16,7 +16,9 @@ import numpy as np
 
 ##### Bandwidth matrix
 # Bandwidth value can be 0 for unreachable nodes
-# Diagonal entries impact the transmission duration for wireless transmissions (wlan0)
+# Regarding wireless interfaces the diagonals of the bandwidth and latency matrices are very important.
+# They determine the duration of the tranmission for THE SENDER. It allows to have a different tx
+# duration per node and per interface. Please cf esds.py for more informations.
 n=2 # Number of nodes including the sender
 B=np.full((n,n),5) # 5Mbps
 
@@ -26,6 +28,8 @@ B=np.full((n,n),5) # 5Mbps
 L=np.full((n,n),0) # 0s
 
 ##### Create the simulator
+# esds.Simulator take at least a dictionnary as a parameter
+# This dictionnary contains all the network interfaces (name as a key) of each node
 s=esds.Simulator({"wlan0":{"bandwidth":B, "latency":L, "is_wired":False},"eth0":{"bandwidth":B, "latency":L, "is_wired":True}})
 
 ##### Instantiate nodes