Identity Resolution creates three types of objects8:
Unified Individual: This object represents the unified profile of an individual, which contains attributes from multiple sources.
Unified Contact Point: This object represents the unified contact information of an individual, such as email, phone, address, or app.
Unified Link: This object represents the link between an Individual object and a Unified Individual object, or between a Contact Point object and a Unified Contact Point object.

This configuration will ensure that Data Cloud only ingests new files from the Amazon S3 bucket and updates or inserts new records into the data stream without deleting existing records. Reference: https://help.salesforce.com/s/articleView?id=sf.c360_a_data_cloud_amazon_s3.htm&type=5

Explanation
This is the first thing a business stakeholder should focus on when considering a Data Cloud implementation.
Obtaining cross-organizational buy-in involves aligning the goals and expectations of different teams and stakeholders who will use or contribute to Data Cloud.
References:https://trailhead.salesforce.com/content/learn/modules/customer-data-platform-basics/get-started-with

Explanation
The Identity Resolution Summary page shows all the above information: Unified Individuals, Last Processing Status, and Matched Individuals. Unified Individuals are the profiles that Data Cloud creates by linking multiple source profiles based on match rules. Last Processing Status shows the date and time of the last identity resolution run and whether it was successful or not.Matched Individuals shows the number and percentage of source profiles that were matched to a unified individual profile. References: Identity Resolution Summary

A window function is a unique requirement of a Streaming Insight query. It defines the time interval for the query to run on the streaming data and the frequency of the query execution. Reference: https://help.salesforce.com/s/articleView?id=sf.c360_a_streaming_insights.htm&type=5