You can type perl -V  (capital V !) to find out Perl's default lib search paths (the @INC array).

But your modules don't necessarily need to be installed in the default search paths.  You can alwas use one of the following to change where Perl looks for modules:

• use lib ...
• the PERL5LIB environment variable
• the -I command line option
• manipulating @INC directly, e.g. BEGIN { unshift @INC, "/path/to/libs" }