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 ar 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 distraction when the child does something you do not like. Walkers can reach higher things. They are learning to climb. Babyproof the house.