Before cooking the corn you should soak the corn husks in water for 30 minutes.
You should fill a large pot or a pot large enough to hold the corn in with hot water and then place the corn husks in the hot water and allow the corn husks to soak for a minimum of 30 minutes but it's okay to soak them longer if you want too.
Some people soak the corn husks overnight too which is also okay but 30 minutes of soaking in water is usually more than enough time for the corn husks.
The longer you soak the corn husks the better so that's why some people prefer to soak the corn husks overnight.