Complex sentence: According to Severloh's autobiography, there were only two or three machine guns emplacements in his section at the time of the landing and just 30 soldiers defending the whole beach.
Split into simpler sentences: According to Severloh's own autobiography, there were only two or three active emplacements with machine guns in his section of the beach at the time of the landing. Severloh claimed that there were just 30 soldiers defending the whole beach.