Go to "Team & Analytics" section on a relevant skillboard.
Option #1: Add position to a member
Go to "Members" tab, choose a person and click on the edit icon.
Click on "Change position".
Choose a new position.
Option #2: Add a member to a position
Go to "Career Paths" tab.
Choose a position and press "Members/Add member".
Choose members in the drop-down list. You can also add a new member via email.