how do I create a ragdoll with fewer than 13 limbs

I want to make a ragdoll with a head, torso, upper and lower arms, upper and lower legs. Unity requires me to designate “root, left hips, left knee, left foot, right hips, right knee, right foot, left arm, left elbow, right arm, right elbow, middle spine, head”, how do I make one without all the body parts?

You gonna have to do it manually. Add Rigidbody, character joints, and capsule/sphere/cube colliders onto the rig based on how you need them.