He's recommending to read/watch SICP and do the examples, which are in Scheme. I think it's good advice to have a Scheme REPL to follow along so that you don't have to worry about the additional overhead of translating to Clojure.
At some point though, as Scheme and Clojure diverge, this method would start to become less useful. But at that point, I would argue, you already know enough to take off in Clojure.