Taking a road signs test to get a learner's driving permit requires you to schedule an appointment with your local DMV and study for the test. In addition to road signs, you need to know basic rules of the road and various safety procedures.
To study for the road signs test, you can download a PDF copy of the manual or take a physical copy from the DMV. Bear in mind that the rules are updated each year, even if they are only small updates, so get the most recent copy. Study the manual diligently to learn about the basics of driving.
Another way of getting prepared for the test is to observe how people behave at a particular sign. Although many road signs are self-explanatory, some might be trickier. Watching what other cars do can give you a clue how to react.
Obtaining a learner's permit if you are in high school typically requires a certification of attendance. Provide this, get a physical/vision exam, and pay the required fee for the test. During the test, answer the multiple-choice questions to the best of your ability. Even if you don't know the answer, use common sense to eliminate answers you don't think are right.