I was already written in another thread, but I will write here also. You
should look at Haskell website[1] it have very nice looking REPL just above
the fold (visible part of the page). I can create something like this using
two of my JavaScript libraries: my Scheme Interpreter LIPS and jQuery
Terminal.

What nice about it is that it have examples on the right and you can click
on them to run them in REPL on the right, and user can also write any code
himself.

I would also include videos of best talks about Scheme that are on YouTube
just like on the Haskell site, videos are easier to consume then written
documents. Maybe same as on Haskell website with videos I would show best
books about Scheme with covers links to PDF if they are free to read online or
link where you can buy them otherwise.

[1] https://www.haskell.org/