Hi all
I wanna make mobile game like Alone developed by Laser Dog
I have many question. 
How do i create levels in unity?
Do i create all in one scene?
Can i make it random?
Thank you
Since this is a general question, and there are so many ways to begin to answer that question, the very best thing you can do is consult the video tutorials made specifically by Unity. The ones for 2D games are here:
There are also some sample projects for you to download and follow. Unity Learn