Complex sentence: The 50th Division was relieved by the 68th Brigade of the 23rd Division and opposite Le Sars, the 69th Brigade took over from the 70th Brigade and tried to bomb up Flers Support on the north side of the Bapaume road.
Split into simpler sentences: The 50th Division was relieved by the 68th Brigade of the 23rd Division and opposite Le Sars, the 69th Brigade took over from the 70th Brigade. The 69th Brigade tried to bomb up Flers Support on the north side of the Bapaume road.