Google Analytics is the measuring tool for advertising ROI and user behaviour.
Once you log into Google Analytics, you can easily find the Google Analytics Profile ID (view id) if you look at the url and take everything behind the
pmarked in blue below.
Google Analytics Profile ID
This is the ID of the view and needs to be inputted as the ids in the format
ga:1234567890, having ga: as a prefix, as per the below.
ids (view id)
To build your data queries, use the by Google provided tool: https://ga-dev-tools.web.app/dimensions-metrics-explorer/
Pre-computed metrics can e.g. include deduplication of users to get to unique users for a timeframe. E.g. a comparison of the last seven days total users vs. daily users per each day individually and then summed up, yields different results. The reason is that a user who visits the page every day will be counted once in the first instance and seven times in the second one.
To avoid this, the time granularity should be the same to the data being displayed.