The first five shots are done with no time limit, shooting as tight a group as possible to confirm that the sights are aligned correctly. After that, shoot it five more times with a five-second time limit. You can use a shot timer, or if you don’t have one, you might try a stopwatch app on your smartphone.
The 5×5 drill is a great way to test whether you have achieved a basic level of competence with handgun marksmanship fundamentals. It can also be used as a way to determine whether you are able to shoot a specific gun well enough to rely on it for defensive purposes.