To add someone to your application , select the option to "Add a family member" at the bottom of the page. Next, you will enter their name, sex, date of birth, SSN, and marital status.
Make sure the circle containing the check mark is green. This indicates that they will be included in your health plan. If you click on the green circle with the checkmark next to their name, you have selected that this person is in your household but will not be included in your health plan.
Once you select a plan and begin your application, you will not be able to go back and remove anyone that was initially added in your health profile. If you added one too many people to your application, you will need to log out and restart the application and create a new account with a different email. Unfortunately, there is no way to manually remove an extra person once you've began the application.