>but I don't know if I need to study and how much time to dedicate to it.

This right here is why we have drivers running over people.

You need to first download the Driver's Manual and read it from the first letter to the last letter. Then go back to the beginning and do it again. Then close it and have someone quiz you. If you fail, go back to step 1.

https://www.mass.gov/lists/drivers-manuals