AWS IoT core to big data

I'm looking for a freelancer to help me with a project that involves AWS IoT Core and Big Data. I need an experienced individual that is familiar with both tools and their usage in the AWS cloud platform. This project requires using the AWS Lambda service to access and process IoT data from various sources. The task entails collecting and combining data from multiple databases, then analyzing the combined data to develop a comprehensive analysis. The output needs to be organized into a format that is easy to comprehend and present. This project also seeks assistance with interfacing with AWS S3 to store the collected and analyzed data. The scope and duration of this project are yet to be determined, so experience in managing projects with deadlines is an advantage.

I need someone to explain me how it works and show me an example.