I would like to set up/create a new business.

Hello there, Linda. I'd be glad to share information about creating new business in QuickBooks Online (QBO). 

You have the option to include an additional business within your QuickBooks Online (QBO) account. It's important to note that each company you establish will require a separate paid subscription. Nevertheless, you can access all of them using the same login details by following the instructions provided below.

1. Go to https://quickbooks.intuit.com/choose-country/.
2. Select Asia Pacific, then click Australia.
3. Choose a product (Simple Start, Essentials or Plus).
4. Click Free 30-day Trial or Buy Now.
5. Since you already have an account with Intuit, click Sign in or Subscribe here beside Already have a QuickBooks Online account?.
6. Enter your Email Address (User Id), First name, Last name, and Password.
7. Click Add new company.

The screenshot below shows you the first three steps. For detailed instructions, go through this article: Create or Subscribe To Another Company. 

Now that you have two companies, you can quickly switch between them to manage everything more efficiently. Just go to the Settings (Gear) icon at the upper right. Then, select Switch Company under Profile as seen in the screenshot below. For more details, check out this article: How Do I Switch Companies?. 

To get started with QuickBooks, you can also open the topics from this link: Help articles, video tutorials, and more.

If you mean something else or you have any other follow-up questions about setting up your business and accounts, please let me know by adding a comment below. I'm more than happy to help. Have a good one!