Noob Question Relating to fRecordSet

I have having trouble retrieving records from the database

have made a connection to the database ... i think ...

//Listings PHP Class
class Members extends fActiveRecord
{
    protected function configure()
    {
    }
}

//Connect To Database
fORMDatabase::attach(new fDatabase('mysql', 'database_name', 'database_user', 'database_password'));

//Category PHP Class
class Category extends fActiveRecord
{
    protected function configure()
    {
    }
}

I am trying to retrieve details from the categories table and then retrieve them. How do I retrieve the details? Trying to use fRecordSet but it's not returning anything?