Complex sentence: Haig called the plan a proposal for a frontal advance of equal strength along the front and directed Rawlinson to consider advancing beyond the first position near Montauban on the right and at Miraumont and Serre on the left but offered no extra forces to achieve this.
Split into simpler sentences: Haig called the plan a proposal for a frontal advance of equal strength along all the front. Haig directed Rawlinson to consider advancing beyond the first position, near Montauban on the right and at Miraumont and Serre on the left but offered no extra forces to achieve this.