Complex sentence: He joined the Nazi Party in 1924 and became a member of the Sturmabteilung, better known by as the SA. Veller reached the rank of an SA Brigade Führer and was named the SA Führer for the Dusseldorf sub-district.
Split into simpler sentences: He joined the Nazi Party in 1924, becoming a member of the Sturmabteilung (SA) at the same time. He reached the rank of an SA Brigade Führer and was named the SA Führer for the Dusseldorf sub-district.