How to create frontend for REST?

Question

Angular

There is a mobile application, there is a rest interface with which it works. There was a need for a web version. Since I am doing 90% of the backend, knowledge about the frontend is limited to banal scripts using jQuery and basic layout. How to do, for example, authorization by post on rest? I want to use angular, but I don’t understand at all how to approach this. While the need to make at least authorization, a request to the server with an authorization token and display some data from the server. If the user is not authorized, display an authorization request. I would be very grateful for your help!