Hi @nbulian Welcome to Auth0 Community.
It looks like you have got RESTFul API setup with Lumen. In order to register and allow user to login, you will need a client application which you can build with any number of frontend or mobile technologies. Checkout our Single Page application or Native/Mobile App quickstarts Auth0
Essentially you will be implementing SPA + API or Mobile + API architecture scenario as documented here Single-Page Applications (SPA) with API
Mobile Applications with API