How to add a specific hero to station. I got a new gold hero but it is not showing in station?

Was the new hero a combat hero or a development hero? You can check in the Heroes menu.

Combat heroes are added to the legions in the legion menu or through a Training ground. You will need to have researched to unlock the hero slots.

Development heroes are found in the lists in the Town hall -> Station option. You will need to upgrade the town hall to increase the cost capacity to let you station more heroes.