Authorisation and authentication API

Hi all, I am working on a project that with a team of developers from other platforms. I am supposed to create two separate  Api end points for authentication and authorization for customers and staffs, there will be a super admin who will created by default and who will subsequently assign roles to other staffs. I am actually new to dotnetcore and really needs help urgently to tarcle this problem. I will appreciate ant help from anyone. THank you