Add missing step to blinky README.
diff --git a/README.md b/README.md
index 405d33b..a77e004 100644
--- a/README.md
+++ b/README.md
@@ -39,7 +39,13 @@
You will need to download the Apache Newt tool, as documented in the [Getting Started Guide](http://mynewt.apache.org/os/get_started/introduction/).
-2. Build the blinky app for the sim platform using the "my_blinky_sim" target
+2. Download the Apache Mynewt Core package (executed from the blinky directory).
+
+```no-highlight
+ $ newt install
+```
+
+3. Build the blinky app for the sim platform using the "my_blinky_sim" target
(executed from the blinky directory).
```no-highlight
