diff --git a/docs/hacking.txt b/docs/hacking.txt
index 20d7477..be97627 100644
--- a/docs/hacking.txt
+++ b/docs/hacking.txt
@@ -1,6 +1,10 @@
 This requires the source checkout from GitHub,
 e.g. https://github.com/brendano/ark-tweet-nlp
 
+The checkout should have all necessary resources EXCEPT a trained model.  One
+can be downloaded from http://www.ark.cs.cmu.edu/TweetNLP (it is packaged with
+the released version).
+
 Setting up Eclipse
 ==================