We are learning about this in history, and I asked my teacher this question, but she couldn't answer. How can a trench be dug during war? Surely your body would be sticking out while you dig, making you a target. And also, it would take a while to dig enough for all the soldiers to fit.
Fortunately for you this is one the sub's frequently asked questions, so you can consult this thread, In trench warfare, like what was seen during WWI, how were trenches excavated close to the opposing army's front line without being overrun or shelled to pieces?, which has a number of more detailed answers to your questions than mine. The short version is that it was primarily done at night, and methods used often involved digging forward from pre-existing trenches.
