I am doing research on the following 3 types of tests for Autism Spectrum Disorder: ASRS (Autism Spectrum Rating Scale), CASD (Checklist for Autism Spectrum Disorder), and GARS-3 (Gilliam Autism Rating Scale- Third Edition)

I am not too sure how to approach this:

I have hit a wall trying to find information on the characteristics of the normative sample (standardization sample) in terms of age, race, geographic region, gender, dominant language, and what percentage of the normative sample consists of these characteristics. (if available). Describe the sampling procedures and what was the size of the normative sample.

and this:

Evaluate each test's normative sample based on the anticipated populations served by one's specialization or related profession. My profession is education.

Do the characteristics of the normative sample of each test adequately match the characteristics of the population in education? Are the sample sizes and procedures adequate in order to generalize the test results to a population that a professional in your specialization or a related profession would likely assess?

I am not sure where to find more information about this, or how to determine the normative sample.

Any help is appreciated.

Thank you