You have to configure your perl as root. It will ask you questions and most of the times the defaults are fine. After that you are able to install packages from the CPAN archive. Please read the instructions on your screen carefully.
perl - e shell -MCPAN
After a lot of questions you will see a prompt:
Update the CPAN package by typing:
cpan> install Bundle::CPAN
It will install all kinds of things. Ater that install the modules you need to install your modules:
cpan> install Digest::SHA1
cpan> install HTML::Parser
This is one way of doing it, there are others.