How to play better chess?

I've tried doing puzzles and watch GM games (though i don't quite understand the moves), but i still can't improve my chess. My problem is, I don't know how to move my pieces in a real game! I just don't know where to position them!! What should i do??

Do puzzles and play games. That is the best way to improve at your level.

Make goals, plans in your games. Even if they're simple, silly, unrealistic, what have you. It doesn't matter. Make a plan and try to execute it. That's the basis for all piece placement. You'll get better at making plans, and you'll make better plans with experience, but for now, let that motivate where you put your pieces and you'll at least have something you're playing for. Eventually you'll have to make good plans, but knowing what a good plan is also comes with experience.