Take appropriate classes in high school to help you with your future training in carpentry. These include mathematics, geometry, physics, general shop and mechanical drawing.
Attend a vocational school or trade school once you graduate from high school that offers career path training in carpentry. You might also be able to obtain a degree in this field from a community college.
Gain part-time employment as a carpenter's helper who specializes in deck installation. This can help you receive informal training in deck installation, and it can be done while you receive an education in carpentry.
Complete a formal apprenticeship in deck installation. Apprenticeships are offered by local deck installation companies and generally last about three to four years. This training will teach you the basics of sketching deck designs, trough framing, the equipment that's needed, various building techniques and finishing the job.