The instruction permit is available at age 14. The driver must hold the permit for six months and log 20 hours of supervised driving that are accident and conviction free. The driver must complete an approved driver's education program for 30 hours in classroom and six hours behind the wheel, after which the driver can apply for the intermediate license at age 16 with written approval of parent or guardian. After driving accident and conviction free for 12 months, s/he can apply for full license at age 17.
So the three stages to GDL (Graduated Driver License) are: instruction permit, intermediate license, and full license.