best Design Pattern

there is a winform application with some layer :
1- IDAL
2- DAL
3- IBLL
4- BLL
5- Tools
6- Model
7- UI

Im define Repository And Unitofwork in IDAL & DAL

Repository inherited from Unitofwork or inverse?
where is location Layer for domain model from DB?
where is location Layer for view model?
where is location Layer for WebAPI?