Relics room is in the kitchen of the community house though According to the signs @ Mr V, Your get used to it in no time ^^ Just learn you basic crafting
I didn't even know what creative mode was until surprize bulldozed the house I spent 4 hours building. So admins actually don't get away with using creative mode.
It means your inventory is not shared between the modes. So if you were carrying some diamonds in the inventory in creative mode, it wont be available when you switch back to survival.
when I switched to survival I lost my inventory but whatever I had equipped in the "quick select" boxes (dunno what they are really called) I still had. I did get rid of them though.