There is no one-size-fits-all answer to the question of how to gain mass, as the amount of weight you will need to gain will vary depending on your starting point and your goals. However, there are some general tips that can help you to bulk up:
1. Eat more calories than you burn. In order to gain weight, you need to consume more calories than your body burns off in a day. This means eating more food than you are used to, and making sure that the foods you eat are high in calories and nutrients.
2. Lift heavy weights. To build muscle mass, you need to lift weights that are heavy enough to challenge your muscles. This means lifting weights that are close to your one-repetition max, and doing multiple sets of each exercise.
3. Get enough protein. Protein is essential for building muscle, so make sure to include plenty of protein-rich foods in your diet. Good sources of protein include meat, poultry, fish, eggs, and dairy.
4. Rest and recover. When you are working out hard, it is important to give your body time to rest and recover. This means getting plenty of sleep and taking days off from training.