Complex sentence: Falkenhayn was still on his journey south from Aleppo, he would arrive at Jerusalem to establish his headquarters in the German Hospice on the Mount of Olives, during the evening of 5 November.
Split into simpler sentences: Falkenhayn was still on his journey south from Aleppo. He arrived at Jerusalem, to establish his headquarters in the German Hospice on the Mount of Olives, during the evening of 5 November.