To create your Grassroots Labs account, click on the "Login". On a desktop computer, the button is in the top right of the page.
On a mobile phone, tap on the menu button in the top left (3 horizontal lines).
From there, click on the login button.
When the login screen comes up, under "Don't have an account?", click on the "Register Now!" button.
You will then see a registration form. Complete the form and click "Register".
You will then get a verification email to confirm your email address. Find that email in your email client and click the verification link inside. NOTE, you will not be able to log into your account with out clicking the confirmation link in this email.
Voilà! Your account is now activated and you are ready to purchase your tests.