To reach the CCL HarbourFront, you just have to take an
escalator up to the concourse level from NEL HarbourFront and go
down another set of escalators, all within the existing paid area
(the current one being fenced up now).
remember seeing a long white temporary wall along the ticket
office side of the station? that is the connection to the CCL
side.
contrary to popular belief, HarbourFront has been built with
provisions for CCL, that's why its so easy to construct the
connection now.