[SRILM User List] lattice-tool

[ali sadiqui]

hi,
I am a beginner SRILM,
I would like to create a lattice from corpora
"A B{b1, b2, b3) C" and then create a language model
I know I have to use the tool lattice-tool, but how do I proceed, I was stuck there.  I guess I should create a file-format pfsg but.
If so:
            How to define the nodes?
            Calculating the cost?
Is this is a manually or using a command?
In short, how to fill it?

I am very grateful for your help.
thank you for your help