Hello and welcome.
Originally Posted by mmom
...where do we start ?...
You may wish to begin with research. You found this forum, so you are well on your way...

Lots of great info on the Davidson Database (link- http://www.davidsongifted.org) including articles on identification such as Profiles of the gifted and talented (link- http://www.davidsongifted.org/db/Articles_id_10114.aspx)

Hoagies Gifted Education Page has great info including tests and test results (link- http://www.hoagiesgifted.org/highly_profoundly.htm)

Kids may often do best when given a challenge worthy of their potential and a cluster group of kids with similar readiness and ability.

Here's a facebook page that may be of interest https://www.facebook.com/GiftedSupportCenter