How to gain weight?!?

Ok well im 14 year old girl & weigh 108. I need to gain weight im like 5'4 or something close to that , i mean im skinnyer than alot of people but im bigger than some people too. But like my boobs arent that big but there growing , & my butt is kinda big but my thighs are like chicken legs ! i seripus , I need help , & i dont want to gain mussel so dont say to exersise i want nice legs , not mussely ones. so please help , !!!!!!!!!!!!like what foods to eat