For 'big data' data modeling, these courses seem ok:
https://www.coursera.org/specializations/data-warehousing#courses
https://www.coursera.org/learn/big-data-management#syllabus
Do some light reading on kimball, inmon, star schemas, then watch this: https://info.dataengconf.com/hubfs/SF%2018%20-%20Slides/DE/From%20Flat%20Files%20to%20Deconstructed%20Database.pdf
Data Modeling in the traditional sense of ETL is a dying. Point being your effort may be better spent learning other things.