How to become expert in COMSOL

Hi Guys,

I am working on COMSOL 4.3a from last three months but still facing some difficulties to become expert in its use. I am not from Engineering background so don't have any experience about simulation studies before but for my current PhD work I need to do simulations of fixed bed reactor for steam reforming of Methane etc. There are some models available in model libraries & I have already gone through them but they have given only instructions to have practice. They have not mentions about physics behind it or they might have assumed that user is aware about these things. When I am practicing some models there are some errors coming after computing, because of lack of knowledge I can not do anything in it and really feeling very sad. Can anyone suggest me what should I do? some basic books for simulation? from which I understand more about simulations studies? I will be more happy to interact with someone who is working in the same fields like kinetic study of steam & dry reforming reactions or doing simulations of reactions in fixed bed reactors so that I can discuss in much details with him or her.

Thanks & regards,
Lalit