That will tell you what group it belongs to. Insects have six legs, two antennae, and three body sections. That's always true. A centipede has over thirty legs, two antennae, and only two body parts. Here is a chart that shows the differences in the arthropod groups.
All insects have three body sections, the head , thorax , and abdomen.
Each part has its own name. Each part has a different job. Insects are a lot like you. They have brains, hearts, eyes, noses and legs. But not all of them are in the same place as yours.