Alright well for starters do what irish cannon said good information on the foods to eat and what guesjn said about the resistance training will help support lean mass, but since you have to "bulk up" gain 5lbs also make sure your doing the compound lifts, bench, squats, deadlifts, close grip bench, military press etc. these lifts help support putting mass on you want between 8-12 reps for adding strength and mass on, mainly your diet is key though. Start off with the food, without eating properly and proper nutrition working out isnt going to do it for you, so just do all that and no cardio till you hit your weight level. By doing all of this there is no reason why you shouldnt gain weight and make sure your eating above maintenance level. good luck and any other questions post em up here or you can pm me if necesary