How do I retrieve my site_id?

Site IDs are all listed in the Data Collection Portal dashboard.

If you do not have access to the Data Collection Portal but still need to retrieve a site_id to use it in an external tool you can go to Data Query and create this very basic dataset. 

Select All organisation as a perimeter (or you can select only the site you want to retrieve the id), then the property Site and the property Site ID. You can then select whatever metric you want but we advise to select Events to have the volume of the site.