Bulking is the process of eating more to enter a calorie excess period that your body will use to build muscles. This indeed requires to do regular workouts, usually involving dumbbells, barbells or other heavy and punishing devices.
You generally aim at eating daily 40x your weight (in kilo) of calories. You also need to watch your proteins intake and keep it at about 2 g per kilo for optimal results.
The side effects include a continously bloated stomach, and most often a gain of fat, which will be taken care of by cutting.