Perhaps you need to get this working on a sdcard before you start playing around. Removing the sd card will take you back to android anyway
@bubblegum57 is correct. If you have absolutely no idea of what you’re doing, as you already state, then master the recommended install ( to external media), before you attempt anything more complicated. Learn to walk before you attempt to run 
Is it possible to use linux and coreelec together. If yes help me to install ubuntu or ambian on my tv box
You understand → NOTHING
What do You want ?
Waste our time ?
If you wish to dive deep in your state of mind confusion,
in regards to linux on your tv box,
read here:
Good luck!