The two sides in battle each settle into trenches and dugouts on the open ground facing each other. Opposing trenches, which are usually several hundred yards apart, are separated by "middle ground" which is laced with barbed wire and is called "no man's land". Because of the heavy artillery and bombardment which constantly pummels this area, virtually all foliage and other potential cover have been destroyed, leaving the space wide open and almost impossible to cross. The men in the trenches undertake daring raids across the deadly no-man's land, crossing the treacherous ground at great risk and penetrating the barbed wire with artillery attacks or with special rifle attachments devised for this purpose. If they should succeed in reaching the enemy lines, the men first throw a volley of hand grenades into the opposing trenches to wreak destruction and create terror and confusion, then follow by attacking the defenders with bayonets in hand-to-hand combat.
Although I have not seen the movie, in the book, Paul is part of a group assigned to "wiring fatigue" in Chapter 4. Under cover of darkness, he and his comrades are sent to set the poles and unroll the deadly barbed-wire to create a fence protecting his own side's position. Later, in Chapter 9, he engages in hand-to-hand trench warfare against the French.