How new plugin form data get stored into database

Hi,

I am creating a new plugin as an activity. I want to know after clicking 'submit and display' button, which function gets called for storing form data into database. Suppose I have to store 2 inputs(other than general inputs) from users into a new table(mdl_newmodule_param). Where should I write code for taking these 2 inputs from form data and insert into new table?

Thanks,

Pankaj