Hi All. How do I add a second company, as in a second business?

Hello, @stu-logistics.

You'll need to sign-up for a new QBO account to create another company. One company file is equivalent to one subscription.

To put this company under your existing Intuit ID, log into your current company when creating a new account. Simply click on the Add another company button when creating another account. From there, you'll only be asked for an Email address and Password (you should be using the same email address).

Here's more information on how to add multiple companies to your QuickBooks Online account: Create a new company and add subscriptions.

Once done, you can simply switch from one company to another quickly. Here's how to switch companies. 

Let me know if you need further assistance in creating a new company. I'm always glad to help in any way I can. Have a great rest of the day.