Suppose i mastered every coding or programming languages. what is the next step. i mean how will i make an app or a game.

Answer 1

In sololearn you learn only the syntax. You don't realy lean programing.
There is no fast way. In order to realy know how to program you have to learn computer science and practice alot.
You didn't mastered in all languages - you learned all the syntax of them.

Answer 2

make it .give it to a tech company in trade for a job..PS:it works...

Answer 3

Math, Physics, Logics and Programming are the general things that a game developer has to know to create games. Maybe you can google about it or ask some experts for help.