You can go directly to our Intuit Developer website. They can help you further in integrating Laravel to QuickBooks Online.
Just go to Help, choose QuickBooks Online and click the Ask a Question button. Once done, you can sign in using your Intuit Developer account. If you don't have an existing account, you may create a new one.
Feel free to get back to me if you have further questions with the Integration of Laravel and QBO.