Very new to LIGGGHTS

Hi there,

I could just knew that FLUENT-DEM cannot be possible with the "dynamic mesh" problems so may be I have to shift to LIGGGHTS software for the DEM analysis.
I was trying to find some user guide for LIGGGHTS but I couldnt find any wherein I can learn from the core.
Can anyone help me, like how should I start learning LIGGGHTS, I might be having short time to learn though.
Actually I am working on the topic TRIBO-ELECTROSTATIC SEPARATOR for my thesis.

Thank you