In staffing the front of the house, the dining room of a restaurant, you are not only hiring people who will do a very important task but people who will have the principal relationship with your guests. In fact, some of your guests may judge their entire experience based on the personality of the person who serves them. So it's not only what they do and what their experience is but who they are when they do their job. Are they somebody who's warm and friendly and caring? Are they a person who's intelligent and can bring that intelligence to bear in a good way in their work? Are they someone who's eager to work hard and interested in doing whatever it takes to make the guests happy and to give them an enjoyable experience?
When you're staffing a restaurant you have to consider the style of service. Will it require back servers and front servers? Will it require captains or bus people? Is it a style of service that requires a specific group of positions like beverage runners or food runners? How are the different tasks of the restaurant going to be done by the front-of-house staff?
You also need to think about how big your restaurant is. Given the style of the service and the style of your restaurant, how many tables should a server have at one time that they are responsible for? If it is a very intricate style of service they'll be able take care of and manage fewer tables. If it's a fairly casual style restaurant they can manage more guests and take good care of them. Designing your room and the layout of the tables will begin to make decisions about how many stations there are. And that means how many service stations.
You also need to think about the different types of skills that those servers need to have. Will they be the ones making beverage recommendations? Or will there be a sommelier or a wine director or manager who does that? Will they be the person who takes care of the table from beginning to end? Or will there be a team involved in that process?