Complex sentence: Sanford A. Moeller (1886-1960) was an American rudimental snare drummer (a national champion for rudimental snare drumming), author, and educator.
Split into simpler sentences: Sanford A. Moeller (1886-1960) was an American rudimental drummer (Rudimental Drumming). He was a national champion as regards rudimental snare drumming, author, and educator.