Just 15 pounds

I’m new here so bear with me if I say anything wrong or flat out stupid but to put it simply I am Male, 5’6, 17 years old, 125 pounds, and have the fastest metabolism in the west. My family has the skinny genes as I’m told and, have been skinny all my life. I want to start shaping my body so I decided reaching 140 pounds and start really working out consistently with real routines and meal plans is my goal. Except I have no real knowledge or experience in what I should be eating and what I should be doing workout wise. Any help I can get would be amazing and appreciated more than you can imagine. I’m ready to start, just please help put my foot on the right path.