Gaining weight

Hi everyone. Does anyone have tips on gaining weight. I’ve been thin my whole life and no matter what I ate I just never gained weight. I’m pretty much built like my dad (second photo guy on left) I just want to gain weight. One summer I had gained a ton of weight, but only in my face and stomach not on my legs. So I just looked goofy or could’ve been a month pregnant lol. (Last picture) But I need tips on gaining weight healthily and evenly through out my body. I’d rather not take pills or anything I don’t like to. But yeah please and thank you! ♥️

EDIT: i also forgot to mention I played sports most of my life and I’m a very picky eater!