Authentication between Java API and React front end

I am creating a web application which runs a java back end and react front end.

I am finding it difficult to source learning materials about how to implement security/ authentication properly. I know how to implement this in a spring boot application using Thymeleaf and I am currently using spring security to do this here but I'm struggling to find some concise info about how to do it with these two technologies.

I would love if anyone could point me in the direction of some solid resources.

Thank you