How can i gain 6-10 pounds? What should i eat and how much?

I'm 14 years old. I'm 5'3 105 pounds. I'm a very STRICT VEGAN. I use to be chubby before i became a vegan 3 years ago. Now i'm kind of tall and bony. People who know what their talking about please answer. And i'm not going to stop being a vegan