how to build muscle?

K

so i naturally have kind of an “hourglass” figure but i’m really skinny and i wanna build muscle in my ass and thighs and keep my waist small but i don’t know where to start. i kinda have a bubble butt right now but it’s not muscle it’s just fat i guess. i wanna be shaped like 🍐 lol. should i start with working out or changing what i eat or what. someone help pls