1. Go to https://www.google.com/analytics and sign in to your Analytics account. Then, click on "Admin".
2. Click on the "Account" drop-down and select the account under which you would like to add a new website. ( Or the account contains your website).
3. Then, click on the "Property" drop-down and choose "Create new property". ( Or choose your existing website).
4. Fill in your website details and click "Get Tracking ID" button.
5. Copy the Tracking ID, as the image below.
6. Return your site, go to "Website Setting", then, paste the ID you've just copy into Google analytic id (content). Then, click "Save" button.
If you’re not sure your tracking code is working correctly, try one of the options below to check your setup. Check your Real-Time reports.
Come back your Analytics Dashboard. Select Real-Time > Overview. And, you can see the active users on site.