Your teacher doesn't need to do anything for you to get started - please just provide the name and email address of someone that, if contacted, could verify that you do attend the school you have listed, and that you meet the other eligibility criteria (high school age, and resident in the US).
Your school contact might be a Computer Science or Cybersecurity teacher who will work with you closely on the program, or it may be a teacher of a different subject, or a school counselor or administrator, who has heard about the program and told you about it because they think you would enjoy it.
You're also very welcome to just decide to sign up yourself because you've heard of the program independently, through social media, a search engine or a friend. If this is the case, please still provide contact details of someone at your school who could verify your identity on request. You will probably want to tell them you've done this, so they know to expect contact from us - and they may be interested in spreading the word to other students in your school!
If you reach the qualifying standard for the National Cyber Scholarship Competition, we will carry out full eligibility checks - this is when we will ensure we have enrolment verification from a teacher/counselor at your school if we haven't already got this. We will let you know when you have reached the qualifying threshold - so at this point you should tell your school contact to look out for any verification requests from us.