Check all that apply. Learn to type, especially touch typing. Work for a Temp Agency because this will get you exposed to the different job fields inside of Telecommunications. Find someone who is doing the kind of work you are considering and ask them to tell you about their job. Expect to get dirty and work outside part of the time in heat, cold, rain, etc.
Military training is an option.
They have excellent schools and you will be working to gain experience while in the military. I wish that this type of web site was available 25 years ago, but then again, that was before digital watches, calculators, and VCRs. Just career exploration.