How to make ps4 games??

Answer 1

You can forget about making console games if you're just starting learning. Only the highest quality game developers are permitted to publish games for popular consoles.

Answer 2

https://www.playstation.com/en-us/develop/

You have to first become a registered developer. I am not sure if PlayStation has their own tools but they definitely have the information of what​ needs to be included on the disk for it to work on the PS4.

Answer 3

learn C and C++.
Do lot's of maths.

If you want to be an one man army, invest some time in 3d modeling also.