improved readme

Author: yorek

Documentation/README.md

@@ -9,7 +9,13 @@ Here you can find documents that explain in more detail how Trill works, how it
 - HighAvailability: details Trill high-availability support
 - UserDefinedAggregates: introduces a framework for query authors to create custom aggregates
 
-## Getting started with Samples
+## Where do I start from?
+
+You should start by reading the `TrillQueryWritingGuide.pdf` that explains the basic of Trill usage, what is a stream in Trill terms, and how you can create your own application that uses it. This is a *must read* in order to understand how to use Trill.
+
+Once you are familiar with the basics, you can move to `Ingress.pdf` that explain more in detail how to get data in and out of Trill.
+
+## Where are some samples?
 
 All samples are available in the following dedicated repository: