It is simple.
Terminal 1 leads to Concourse C
Terminal 3 leads to Concourse A and B
Terminal 2 (which does exist) has no concourse - all remote stands
Concourse 4 is to be constructed
Maybe I am getting more stupid with age but I am still not clear on this...
So, is terminal 1 being renamed as Concourse C? Or are they two separate areas? From your second line it implies the latter (since obviously terminal 3 cannot be both Concourse A and B). Just double-checking...