How can i install Phoenix os alongside ubuntu without erasing any data?

I’m trying to install Phoenix OS as dual boot alongside with my Ubuntu 18.04 LTS but it’s not going so well. If someone has already done this, I need your help. I downloaded .iso file of latest Phoenix os from the official site of phoenix os http://www.phoenixos.com/en/download_x86 and extracted the files to a folder. I went Super user and created a folder named Phoenix into the root folder and copied initrd.img, kernel, ramdisk.img, install.img and system.sfs into that folder. I downloaded and installed Grub Customizer and created a Grub for Phoenix OS. After completing all these processes when i try to select Phoenix os from grub it shows error: “missing files /phoenix/kernel” “missing files /phoenix/system.sfs”