Hi hvernon,
Welcome to the community family! It's great you're using Squarespace and want to integrate it with QuickBooks Online. QuickBooks makes it easy for you to connect third-party apps in the program so you can bring all your data together. I'll be happy to guide you with this.
To synchronize an app with QuickBooks Online is a pretty straightforward process.
- Go to the Apps menu and choose the My Apps tab.
- Search for the app you're interested in.
- Select the app, then Get app now.
- Review the Authorization page and select Connect.
And that's it!
I hope this helps. Feel free to stop by if you need anything else.