During the Analytics setup process within Site Kit users have the choice to connect to an existing account and property or to create a new one. If you have already manually added your website at analytics.google.com you can choose to connect to that existing account and property.
Do i need to add traking code or something or am i done with google analytics?
There is no requirement to manually add tracking code after connecting the Analytics module within Site Kit.
You can confirm that the snippet has been placed via Site Kit within Analytics settings screen via “Site Kit > Settings > Analytics > Edit”
You’ll also notice the snippet placement when checking your site source code.
Let me know if you have any further queries on this.