They might be hungry, wet, tired, in pain, or need to be held. A baby cannot be spoiled for the first six months. Babies who are picked up when they cry learn that they are safe and can depend on the world. Usually they will cry less later on. As soon as they can talk, they will use words to tell you what they need.
Crawlers often get into things.
Remember to babyproof the house. Use distractions when the child does something you do not like. Give the child the chance to explore safely in at least one room in the house. Walkers can reach higher things. They are learning to climb.