It’s not nearly as dramatic as you may think. The unfortunate truth for Hollywood is that most of WWI was sitting around improving defenses and doing basically nothing.
The conditions were horrific the entire time for most parts but you were not constantly getting out of trenches and charging enemies most of the time.
One of the biggest jobs of men on the front is to constantly check, repair and lay down barbed wire outside of their trenches. This was generally done at night for obvious reasons and generally required hundreds of men to cover the workers doing this.