Admin Forum:How do i set AdminMentor on my wiki?

I went to my admin dashboard and i wanted to add user rights of adminmentor to my user. And then i saw that adminmentor is in "Groups you cannot change". Please help how do i set adminmentor?
 * Adminmentor is a Staff-managed global user group, and so you cannot assign it to users. For more information about Admin Mentor Program, see here.