[antlr-interest] please help me

[Gouasmi Thouraya]

Hello
Please sir
In my project, I have to develop a tool which makes the transformation of a specification in a language Z towards a specification in another language CSP-Z, I already have defined textuellement of the rules for this transformation. I try to find a tool which takes in input grammar of two languages and the rules that I have already defined and to him to make this transformation, and I find that can be this tool answers my needs. In spite of the bank of documentation for the ANTLR I don't understood exactly the steps that I have to make them.
After some reading, I understood that being can I have to write the grammars of two languages but with which tool, with which language and how (with the ANTLRWork?)?
Then what I have to make?
 I have to write a parser? And how?
Please help me, I am a little bit novice in programming, but I am going to make the maximun with your helps.
 
Please answer me the rather possible , I am really in a critical case.
Thank you for your attention