Flux is a new language developed by InfluxData, used for querying and analyzing data in InfluxDB. Katy Farmer, an InfluxData Developer Advocate, provides a tutorial on how to window and aggregate data using Flux queries. She uses a script that routes cryptocurrency exchange information into InfluxDB and aims to compare the actual trading price with expectations. The tutorial demonstrates various steps of windowing and aggregation in Flux, allowing for easy comparisons between Flux and InfluxQL queries. By using Flux, Farmer can make meaningful comparisons and gain insights from her data.