How can I use a generic repository and unitofwork?

Question

I have a service layer which is using unitofwork and Imapper, example given below:

//Service layer
public interface IEmployeeService
{
   Task  AddEmployee(EmployeeListResponseModel model);
}
public class EmployeeService :  IEmployeeService
{
 public async Task AddEmployees(EmployeeListResponseModel mode)
   {
      public EmployeeService (IUnitOfWork unitOfWork, IMapper mapper)
       {
         _unitOfWork = unitOfWork;
         _mapper = mapper;
       }
   private readonly IUnitOfWork _unitOfWork;
      private readonly IMapper _mapper;
}

Question: How can i call this service method "AddEmployees" in one of my class library project? For creating a object of class "EmployeeService" i need to create unitofwork and imapper but i do not know the best practice. Kindly help