Trying to install the Erlang documentation

[Roger Price]

I downloaded otp_src_R10B-5.tar.gz , unzipped and untarred it, entered
directory otp_src_R10B-5 and read the README.  I followed the instructions
to install Erlang/OTP and then read "How to install the Erlang/OTP
documentation".

This calls for me to
        cd <PrefixDir>/lib/erlang
        gunzip -c otp_html_R10B-0.tar.gz | tar xf -

I guess <PrefixDir> is the default /usr/local, but /usr/local/lib/erlang
contains no file otp_html_R10B-0.tar.gz.

Do I have to download otp_html_R10B-0.tar.gz and place it into
/usr/local/lib/erlang, or should this happen some other way?

Should I understand that "otp_html_R10B-0.tar.gz" means
"otp_doc_html_R10B-5.tar.gz"?

Any help would be much appreciated,
Roger