Most important:

What directory do your Website's HTML and image files go?
/home/httpd/vhosts/YourDomain.com/httpdocs
(This is equivalent to the "public_html" folder on many other servers.)

Where to put Perl/CGI scripts?
/home/httpd/vhosts/YourDomain.com/cgi-bin
In other words, the CGI-BIN folder is outside the main folder.
PLEASE NOTE: You can execute CGI scripts in any directory, not just the cgi-bin directory !

What is the path to Perl?
/usr/bin/perl
In most CGI scripts the standard path line is therefore:   
#!/usr/bin/perl

What is the path to sendmail?
/usr/lib/sendmail
/usr/sbin/sendmail