diff --git a/.config.sh b/.config.sh
index aaafc95..21e6f76 100755
--- a/.config.sh
+++ b/.config.sh
@@ -317,6 +317,7 @@ NODE_RED=
 
 # Node-RED multi instance
 # Number of Node-RED instance. default: 1
+#   Must be between 1 and 20 when specified
 NODE_RED_INSTANCE_NUMBER=
 
 # username for Node-RED instance. default: node-red
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e107ce0..1d7bad3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## FIWARE Big Bang v0.38.0-next
 
+-   Clarifies instance number variable for Node-RED (#385)
+
 ## FIWARE Big Bang v0.38.0 - 01 June, 2024
 
 -   Update Quantumleap to 1.0.0 (#382)
diff --git a/config.sh b/config.sh
index aaafc95..21e6f76 100755
--- a/config.sh
+++ b/config.sh
@@ -317,6 +317,7 @@ NODE_RED=
 
 # Node-RED multi instance
 # Number of Node-RED instance. default: 1
+#   Must be between 1 and 20 when specified
 NODE_RED_INSTANCE_NUMBER=
 
 # username for Node-RED instance. default: node-red