LAMP is a server architecture while React is a client library. Before I started learning JavaScript and AngularJS, I also developed web sites and applications completely server-side with LAMP.
IMO, once you have gotten into JavaScript, the biggest challenge is the change you have to make in thinking. No longer is the database so close to the page rendering as it is in PHP/MySQL. If you need data persistence, you have to develop a REST API or use a framework that helps you do that. You then have to use that API in your React application to accomplish what you have once done server-side using PHP.
Since you are familiar with the LAMP architecture, you can use your existing knowledge to create a REST API with PHP for persistence you then use inside your React application which is statically served using Apache.