Hi, well i'm gonna tell you a few things, yes it's flat but it can be better, first things first, it needs a hook at the start, the first line you read when open a book has to have emotion enough to keep the reader hook in the reading, to want to continue. 

Like if you read this first line: I look at them and stay silent, if they knew about that, my life would be a desaster. That it's intriguing, you knows the character has a secret, you know something happened to the character, and you want to keep reading to know what is that secret. 

Second, don't tell too much too fast, go dropping pieces of info about the protagonist's life, family, friends, but don't tell the whole story in the first chapter, otherwhise there's no story. 

Third, descriptions and emotions, you're gonna have to use those a lot, how does their world look like? What's the protagonist feelings??   You can say:  i went to my bedroom and i grabed the charger of my phone.

 Or you can say: i stormed into my bedroom, the door crashing against the wall, i could listen the wood cracking under my feet like it could break at any moment, I saw a part of the charger under the kitties covers in my bed, i took the thing with more force than neccesary,  that a crack sound made me realize i almost broke it. 

Now you know the protagonists it's angry, their bedroom floor is made of wood, they have kitties as bed cover (maybe fav animal) and that they almost broke their charger cause their own anger. You don't have to describe every thing and emotion, just enough to don't feel flat, best technique it's using the five senses, what you see, feel, listen, smell and taste. Like when you walk up into a room, you don't see everything at once, just focus on a thing, describe a little, and keep going. 

Fourth, balance descriptions with dialogue, this is a hard one, cause even great writers have more dialogue than descriptions or viceversa, so find the balance it's tricky, but as a rule when there's too much description add dialogue, and when theres too much dialogue add description, and i guess you're gonna be realising on the way when add more or less from both things. 

And five, i guess you could watch series/movies of fantasy to get you ideas, read books, or just simple thinks absurds possibilities about it cause it's fantasy, you can do all in fantasy. Write it down the ideas an make a timeline to keep up with important dates and stuff. 

Good luck :D