Just follow the below steps:
Step 1. Go to This URL – https://app.aitrillion.com/pricing
Step 2. Choose the plan for AiTrillion (Free or Paid).
Step 3. Create an account on AiTrillion.
You will be automatically logged in to AiTrillion.
Step 4. Select Magento and click on the Next button.
Step 5. Enter your store URL and click on the Submit button.
Step 6. Check and confirm the URL then click on the Confirm & Next button.
Step 7. Download the Extension from the given link and follow the process from here
Step 8. Once the process (step 7) is completed, then go to Magento Admin > Stores > Configuration > AiTrillion.
Step 9. Copy the codes from AiTrillion and put them in the Magento Admin (path specified in step 8).
Step 10. Once done with the entries then click on the Verify & Connect button.
Step 11. Please wait for a while since the process is running. We are setting up your account.
Step 12. Congratulations! Your store is successfully connected and the data syncing started in the background. Meanwhile, you can set up the AiTrillion modules.