Getting started with ANTLR is pretty easy if you start playing around with some existing grammars and read some introductory material. As you progress, you will want to check out more advanced topics and play around by working with bigger grammars. Also please join us on the antlr-interest mailing list for active discussions on ANTLR and languages.
The Definitive ANTLR Reference
To get the most out of ANTLR, you should get The Definitive ANTLR Reference: Building Domain-Specific Languages. The book describes all features in detail, including the amazing new LL parsing technology, tree construction facilities, StringTemplate code generation template engine, and sophisticated ANTLRWorks GUI development environment. You'll learn all about ANTLR grammar syntax, resolving grammar ambiguities, parser fault tolerance and error reporting, embedding actions to interpret or translate languages, building intermediate-form trees, extracting information from trees, generating source code, and how to use the ANTLR Java API. The definitive reference is required reading to become an advanced user. For example, Part III provides the only thorough explanation available anywhere of ANTLR's LL(*) parsing strategy.
If you are totally new to ANTLR v3, follow these steps:
For building projects manually or with ANTLRWorks IDE:
Make sure you have installed the Java JDK (not JRE)
Try modifying an existing grammar; change actions and rule elements to see what happens. You can look for grammars in the ANTLR grammar list (though, most of them are currently v2 grammars) or take a look at some of the ANTLR v3 examples.
That should give you a taste of how to run ANTLR on a simple grammar and some clue about how to build a recognizer and translator. From here, you should start with an existing grammar that is similar to your intended application and start modifying it. There are a number of Tutorials you can look at that explain some of the basics of building translators and provide some grammars to tweak: