777 GPS HSI

ok, i filed a flight plan IFR-GPS from atlanta to miami but started on the runway and got clearance. i flipped the nav/gps switch to gps but i'm not getting any info on the HSI. everything is there if i open the GPS but i just want to use the HSI and not the map. why isn't any information showing on the HSI. do i need to put a VOR freq. in the nav radio? i didn't think i needed to do that. by the way, i did this last week but can't remember what i did to get the info to come up in the HSI. am i making sense here? hope so. i was thinking there would be some sort of name or initials of the destination airport like kmia or something but there's nothing that relates to the flight, no heading for it at all or anything else. it's not empty but just nothing that relates to the flight that i can see. i've overlooked something. william