How do you hack in to Pokemon game like those on YouTube

There is a game hacking system that u can buy for about 15 dollars online and sometimes in stores but very rarley and it is called a gameshark or an action replay. you can get one for ur gba and i think for ur Nintendo ds but when u use it there are codes online that u need to put in it while its in ur Pokemon game. on websites there should be instrutions on how to put the codes in but u must listen to what i am about to say here..........
THE GAME SHARK AND ACTION REPLAY CHEAT CODE SYSTEMS HAVE A VERY HIGH CHANCE THAT IT COULD MAKE UR GBA OR NINTENDO SYSTEMS CRASH SO IF U R UNCARING ABOUT ANYTHING HAPPENING TO UR SYSTEMS THEN GO AHEAD AND BUY THE ACTION REPLAY OR GAMESHARK SYSTEMS BUT IF U EVEN CARE ONE LITTLE BIT ABOUT THEM I RECOMMEND NOT GETTING THEM AT ALL.......hope this helps!!!!!!!!