A war of attrition is when an army has to fight with the men and supplies it has at hand until it runs out. If one nation has more than the other, the outcome of the war will be in his favor. Though this was abandoned later on in the war.
Before they began to attack a countries artillery would bombard the enemy. What this means is attacking a fortified place with explosives like grenades, rockets, shells etc. What would happen was they would attack the trenches to rip holes in the barbed wire and destroy the enemy's communication trenches and the front line. After 1914 the tactics were changed so that poisonous gas was released against the enemy and tanks and aircraft would attack the enemy, tanks could break through the trench system. I can imagine that this was a panic-stricken time for the troops that may have felt suicidal in a way.
After the intial bombardment the troops armed with bayonets would go 'over the top' of their trenches and charge across the burnt out shell that is no mans land, through the deep shell holes which provided shelter in hope of overpowering the enemy and taking their trenches, this often resulted in suicidal and hopeless attempts from the troops who knew that they could do little to affect the outcome. 'After the bombardment he sent out an officer and twenty-five men as a feeling patrol. As they reached the No Man's Land there was a burst of machine gun and rifle fire. Only two men regained the trench... The Sergeant Major sad 'It's murder, Sir'. Of course it's murder, you bloody fool' I agreed, 'but there's nothing else for it, is there?' quoted from a British soldier, R. Graves after a bombardment. 'The bombardment stops. The attack has come... We use machine guns, rifles and band grenades. The enemy cannot do much before they are within forty yards. A whole line has