Flowable newbie questions

Hi everyone, I’m starting using/learning Flowable and I have some basic questions:

1- How is the standard way to save information in the different task of a process?, can i have my own table with data and make a relation with the task?, is this a standard functionality or I need to create my custom logic to acomplish this?

2- Looking at the tables generated by the engine I realize that there are some tables for users, and groups, but I cant find where those tables are realated with the tasks or processes, it is needed to create custom logic here?