Complex sentence: To deal with these Topf & Söhne installed a further two 8-muffle ovens, and another five 3-muffle ovens had also been installed at Auschwitz-Birkenau by March 1943.
Split into simpler sentences: To deal with these Topf & Söhne installed a further two 8-muffle ovens. A further five 3-muffle ovens had been installed at Auschwitz-Birkenau by March 1943.