Thanks for the comments! React and Redux are two separate technologies (in fact, you can use Redux with another view library if you want) and as such you can learn them completely separately.
But that being said, from my own personal experience, I would recommend building stuff with React first. You’ll stumble along the way and see some of the pain points from just using React, and then when you decide to learn Redux (or some Flux implementation), you’ll realize why it makes sense of use that technology. In general, that’s my recommended strategy — learn as few technologies as you need, build and hack stuff together, and then learn a better way to do it!