With the exception of the Lead Link of the largest circle, Lead Links are assigned just like any other role.  
The assignment must be made from the parent circle. This is because a Circle, from its parent circle's 
point of view, is just another role.

  • In the below example, "Market Place" is the sub-circle for parent circle "GCC":
  • To assign a Lead link to "Market Place", click on the GCC name and within that page find the person icon with the plus sign, to the right of the role "Market Place":

  • Enter the name of the member and click "Assign Lead Link" to confirm.

See also:

How do I assign the Anchor Circle's Lead Link?

How do I assign someone to a role?