You've come to the right place, @fclancy. I can help with tax rates in QuickBooks Online (QBO).
There are currently two sales tax setups in QBO, regular and automated. The regular system is designed for a user to set up and track sales tax, such as adding rates and agencies. This system allows a user to manually set up multiple rates and combined rates. For additional information on this, please see the following articles:
The Automated Sales Tax feature is designed to automatically track sales tax, without the need to manually select a rate on a transaction. This is calculated by various information, such as business location and shipping location. I suggest the following article for further insight into this: Set Up and Use Automated Sales Tax.
If you're unsure of which version that you're using, I'd recommend seeing if you have the same options mentioned in the article and video. Should you not, then you likely have the Automated Sales Tax feature.
That's it. I'm confident that this will get you started on the right path for sales tax.
As always, I'm just a post away if you should need anything. Hope you have a good rest of your week.