I have a problem with adding server into "Closest server rule" Everything is grey out, i can't add any server into the box.

Current Setup:
1x Primary Server
1x Satellite Server
1x Client

how do i make sure the client agent will download patch/bundle from the satellite server instead of the primary server. I do see the Client Agent Properties (Closest Server for Roles) there are Satellite server and Primary server in the Content & Collection categories.