Cannot access theme store on Samsung Galaxy J3 (2016) (SM-J320ZN)

[Android Central Question]

So I own a Samsung Galaxy J3 (2016), and ever since I have got it, I have seen other videos on youtube about people reviewing Samsung Galaxy J3 (2016)'s. I have noticed that on the videos, they have got the theme store. But on my phone, the Theme store is nowhere to be found. It shows up in Smart Manager as a 13mb app but I can't find the app in settings or any other of the usual places. Incase its something to do with my model or where I live, its model number is SM-J320ZN and I live in Australia. Any help? I also have another problem of when I restart my phone, sometimes apps on my home screen will disappear, or stack up on top of each other which shouldn't be possible in Android 5.1.1. But anyway, any help or advice is appreciated.