how can use identity for login and register in multi tier programming

hi
i want to use multi tier programming.
DataLayer,ServiceLayer,DomainClass and MainProject.
and i use structureMap Library.
in the past,i did not use tier programming. so i had IdentityConfig.cs and IdentityModels and used for Register and Login and easily.
and i had IdentityConfig.cs in App_Start folder.
now i do not have App_Start folder and IdentityModels .
so i do not how can i use this classess and write my register and ligin page in this case. i mean in muli tier.
if more explain is necessary i can put my all codes.