diff --git a/tempest/common/dynamic_creds.py b/tempest/common/dynamic_creds.py
index d374be4..a63af38 100644
--- a/tempest/common/dynamic_creds.py
+++ b/tempest/common/dynamic_creds.py
@@ -154,6 +154,20 @@
         return cred_provider.TestResources(creds)
 
     def _create_network_resources(self, tenant_id):
+        """The function creates network resources in the given tenant.
+
+        The function checks if network_resources class member is empty,
+        In case it is, it will create a network, a subnet and a router for
+        the tenant according to the given tenant id parameter.
+        Otherwise it will create a network resource according
+        to the values from network_resources dict.
+
+        :param tenant_id: The tenant id to create resources for.
+        :type tenant_id: str
+        :raises: InvalidConfiguration, Exception
+        :returns: network resources(network,subnet,router)
+        :rtype: tuple
+        """
         network = None
         subnet = None
         router = None
diff --git a/tempest/test.py b/tempest/test.py
index b32beaa..4bc0ae2 100644
--- a/tempest/test.py
+++ b/tempest/test.py
@@ -350,11 +350,14 @@
 
     @classmethod
     def setup_credentials(cls):
-        """Allocate credentials and the client managers from them.
+        """Allocate credentials and create the client managers from them.
 
-        A test class that requires network resources must override
-        setup_credentials and defined the required resources before super
-        is invoked.
+        For every element of credentials param function creates tenant/user,
+        Then it creates client manager for that credential.
+
+        Network related tests must override this function with
+        set_network_resources() method, otherwise it will create
+        network resources(network resources are created in a later step).
         """
         for credentials_type in cls.credentials:
             # This may raise an exception in case credentials are not available