BuildAvatar from new rigged mesh

Hi, I have two rigged objects on my scene but I only have avatar on one of them. Then, what I do to anymate the second object (the one without avatar) is to try to put the first object's avatar into it. The problem is, if I do so, the second object gets automatically scaled when animating because of the avatar.

Then, I decided to create a new avatar from scratch with unity, for the second avatar but I can't understand how to do it.

I did something like that:

for (int i = 0; i < bones.Length; i++) { scanDescription.human[i] = new HumanBone(); scanDescription.human[i].boneName = bones[i].name; scanDescription.human[i].humanName = bones[i].name;

      scanDescription.skeleton[i] = new SkeletonBone();
      scanDescription.skeleton[i].name = bones[i].name;
      scanDescription.skeleton[i].position = bones[i].position;
      scanDescription.skeleton[i].rotation = bones[i].rotation;
      scanDescription.skeleton[i].scale = bones[i].localScale;

}

where bones is the Transform[] with the positions of the bones of the rigged objects, but this is not working. The thing is, I only have those transforms but I don't know what to put on every skeleton and what to put on every human name, bone name and so on. The avatar must be humanoid (the existing avatar is set to humanoid)

The second question is, on the imported model with existing avatar, I can use the "configure" tab to see the mapping of the bones but I cannot do the same with the new created avatar