Complex sentence: British VIII Corps led the attack with three armoured divisions, supported by British I Corps on the eastern flank and the Canadian II Corps on the western flank, who were launching their own attack codenamed Operation Atlantic, to capture the remainder of Caen.
Split into simpler sentences: British VIII Corps led the attack with three armoured divisions, supported by British I Corps on the eastern flank. The Canadian II Corps's portion of the operation was codenamed Operation Atlantic; the Canadians were to operate on the western flank of the British 8th Army and capture the remainder of Caen.