As the main admin, you will need to add yourself as a home visitor. You will need to give yourself a different username than the one you are using as admin. You can add a number or something to the end.
You can then disable that login so it doesn't count as a "billable" user. You would disable from the home visitor profile after it's been created.
You don't need to use this login. You can do all the necessary work from the admin login, this will just add you to the HV dropdown.