How to desing and run the character.etc

MY QUESTION IS THAT HOW I MAKE A REALASTIC WORLD AND HOW I DESING MY OWN CHRACTERS AND HOW I CAN MAKE MY CHARACTERS GUNS AND HOW TO MAKE THAT CHARACTER AND WORLD WORLD RUN AND PLAYED TOGETHER I HOPE YOU UNDERSTAND WHAT I AM TRYING TO SAY SIR/MAM PLEASE HELP I WANT TO MAKE A FPS GAME REALSTIC LIKE CALL OF DUTY & BATTLEFILED 5 I KNOW HOW TO ADD SOUND AND EFFECTS BUT TO MAKE MAKE REAL WORLD MAP AND CHARACTERS OF MY GAME AND HOW TO RUN THAT HOW TO RUN THAT

THANK YOU !! FOR READING PLEASE TELL ME THE SOLUTION OR ANSWER I WILL BE GRATEFULL TO YOU