in CA, you do not have to take a drivers ed class in order to get your permit if you are over 18.
the best way to do it is, make an appointment online for the DMV. study the handbook front to back. most of the questions are common sense but study nonetheless. the day of your appointment, arrive about 10 to 15 mins early so that you can fill out the form before you get in line. once you're in line, they will take your application. give them your EAD and SSN when they ask for it. they will give you the test and point you to an another where you can take the test.
once you're done, they will grade it right there and then. if you pass, then you will get your permit. even though you're over 18, having a permit DOES NOT mean that you can drive alone. you will need to have somone who has a DL and over 25 in the car with you when you drive. and yes, it says that in the handbook.
you will also need to take a vision test. it's simple and basically the same as at the eye doctor. if you wear glasses normally then they will ask you to take the vision test without your glasses first and then with your glasses. if they determine that you need your glasses while you drive, your permit and DL will state say. and yes, if a cop pulls you over and you are not wearing your glasses, they can give you a ticket for that. most times, they will give you a warning, if they say something about it.