He attended the local Arts and Crafts school and honed his skills by making copies of old paintings.
In 1909, he passed the entrance examination at the Academy of Fine Arts, Munich, and was assigned to the drawing class of Heinrich Knirr.
After a year of study with Landenberger, he took composition classes from Adolf Hölzel, whose teaching methods differed from anything he had experienced before; treating art as a type of science.
That same year, Hölzel was able to secure him a position painting murals in the main lobby of the upcoming Werkbund Exhibition, where he worked with Oskar Schlemmer and Willi Baumeister.
Following the outbreak of World War I, Stenner and Schlemmer volunteered and were assigned to Grenadier Regiment #119 ("Königin Olga").