Preprocess function

Hello,

I am doing a module similar to this, for adding a new views style and I having trouble with the preprocess function.

I saw your module uses the template preprocess and you always get the function called.

I am having trouble, because I have to change the weight of the module, do you do that too? (I cannot see where you are modifying the weight module, in case you are doing it)

How is the proper way to do the preprocessing?

Thanks for your help