Hear me out: gaining weight in right places

okay I’m not like super super skinny I’m at a fine weight where my stomach is flat and all but my legs are pretty skinny and I wish I could gain some weight there and Yk my butt I weigh 112 like my body isnt bad where i should be complaining but i still find myself not happy because i see my friends with much more on their thighs and stuff since my stomach is kinda ish flat I don’t complain that much about myself but I feel like if I just ate and ate it’d obviously all go to my stomach and knowing myself I’d hate my body even more so I know I’d have to work out to keep my stomach flat but what are some tips on eating / working out?