You don't. You just perform the actions required to pick up a new language. I've summed up a few introductory details about React.
What is React? React is a JS library for designing UI or UI components.
Who invented React? React was created by a Software Engineer named Jordan Walke.
Where was React invented? React was invented by Jordan Walke while he was worining in Facebook.
When was React invented? React was first released on Facebook's newsfeed in 2011.
Why was React invented? React was designed to give developers the chance to design web applications that support dynamic data without reloading the page.