Depends whether you learn best by reading [1], answering some interactive questions/koans [2], or downloading and playing around with a ToDoMVC app example [3][4][5] or a mixture of the above. Feel free to join the #clojurian Slack channel [6] if you need help.
As a beginner, I recommend you looking at the Reagent [7] or Rum [8] React library first, than you can look at something more complex and full-featured like Om [9] later (whose author is also a ClojureScript core contributor @swannodette).
PS: You can also learn by implementing a Dashboard like this [10]. Disclaimer: I am the author of this library.
[1] http://funcool.github.io/clojurescript-unraveled/
[2] http://clojurescriptkoans.com/
[3] http://todomvc.com/examples/reagent/
[4] https://github.com/reagent-project/reagent/tree/master/examp...
[5] https://github.com/gadfly361/cljs-todomvc
[7] https://reagent-project.github.io/
[8] https://github.com/tonsky/rum