How do you think is the best way to impact knowledge to a special child or children?

first, assess his learning needs and ability to learn.
This will help you identify what approach you should use.
Next, identify his interests.
Knowing whether he responds to music or visuals will not only allow you to determine where to inject knowldge but will also help you gain and maintain his attention.
lastly, be patient and consistent.

Let him search & find it by himself