You must be a NATA member in good standing to use Go4Ellis. When you sign-up you will be prompted to enter your NATA member number.
If you don't know it, don't worry, you're not alone. On the top of our sign-up page there is a link that says "Forgot Your NATA Number?" (see screenshot)
Just click the link, follow the prompts, and verify your email, and your member number will pop-up.