I can share some information on how to add another business account, @ryansaunders1-ho.
One QuickBooks Self-Employed (QBSE) account is equivalent to one self-employed business. If you have multiple self-employed businesses, then I suggest subscribing to another QBSE account. It can only track income and expenses throughout the year and estimate quarterly tax payments for a single business.
You can create a new account using this link: New QuickBooks Self-Employed account.
To know more on how it works, check this article: QuickBooks Self-Employed Overview. All you need to know about QBSE is outlined in that article.
Let me know if there's anything that you need to know in setting up your account or if you have any other concerns with your account. I'm always here to assist. Take care and have a great rest of the day!