1-) What is it for?
Google Analytics is an incredible tool, it allows to know how long does a visitor stays on your website, which pages were seen, the source of your visitors, etc.
You can have access to lots of important information and be able to measure the exact impact of your advertising campaigns for example. You will be able to better understand your audience and thus better respond to their needs. You will have the opportunity to compare your current performance with your previous campaigns and you will be able to control your budget. Brief, this tool gives you a concrete way to track visitors activity on your website.
2-) create an account
First, create a Google Analytics account in order to get your Google Analytics ID. Go to the Administration tab at the bottom left of your account, click on Tracking Information and then click Tracking Code. You will find your ID. Just copy the code to be able to integrate it on WebSelf.
3-) adding the code on WebSelf
Go to your WebSelf site, then on the vertical management bar at the bottom left of the editor, click on the "Settings" tab. Then click on the tab "Code and tracking", you will find at the top right the heading "Google Analytics tracking ID". You must add the code in the box provided for this purpose and do not forget to save before leaving.
Go back to your Google Console account and click on the "Validate" link.
Once you have verify your site ownership, your site will appear in the Dashboard of your Google Analytics account.
To learn more: how to use Google Analytics?