If you've recently tried to connect Google Analytics to your site, firstly, make sure that you've inserted the correct tracking ID (G-XXXXXXX) in your website's integrations settings.
It's also important to update your website once any code or ID is added, edited, or removed from the integrations settings, as this is how the changes are updated in your website's source code.
You can inspect your page to see if the tracking ID can be found in your website's source code:
Access your website online
Inspect your website (open the Elements tab)
Copy your Google Analytics tracking ID
Search for the tracking ID in your website's source code: click anywhere on the code in the Inspect tool, press CTRL+F (Windows) or CMD+F (macOS), paste the ID, and hit enter to search
If everything seems to be set up correctly, but you still can't see any data in Google Analytics yet, don't worry – the first reports arrive 24 hours after successfully integrating Google Analytics into your website.
Yet, if you're eager for statistics, you can check the realtime report. Open your website, and in another tab go to Google Analytics → Realtime → Overview. If you have your website open, you should see at least one visitor (yourself) there which means that your Google Analytics has been set up correctly:
To learn more, check out Google Analytics Academy courses.