To configure:

a) Create script cache
1) If your web server is allowed to write files in the same directory
where your HTPL documents will be stored, you don't have to do anything.
Continue to step b.
1a) Option 1 is always preferred. Try to run your webserver with SUEXEC.
If you are a virtual hosting user, ask your administrator to install
cgiwrap, and edit the .htaccess file created by HTPL, substituting
/cgi-bin/htpl.cgi according to the instructions that come with cgiwrap.
2) If you are installing HTPL as root, and are going to use it only as a
mod_perl extension, substitute ./configure by ./configure --enable-modperl
Continue to step b.
3) Running the CGI mode with a non previlleged httpd, you will have to
create a cache directory to cache preprocessed scripts. 
Under each directory you want to enable for htpl, create a world writable
htpl-cache directory:
mkdir htpl-cache
chmod 733 htpl-cache
Since your scripts will be world writable, it is necessary that you use
the dependency database to ensure the integrity of your scripts. Using the
dependency database, your runtime script will always be recreated if it
has changed since created. You must have Berkeley DB 1.85 installed for
it. Substitute ./configure --enable-depdb

b) Install the binary
1) To install HTPL on your machine:

./configure
make
make install
make build

Have your CPAN.pm module configured and type:
make CPAN

2) To install HTPL on a virtual hosting account:
./configure
make
make install
make build

Experimental module installation can be used by having CPAN.pm configure
itself, then run: make CPAN
to install the modules in the cgi-bin dir.

3) To install HTPL on a virtual server kernel account:
./configure --with-vserver
make
make install
make build
make CPAN NOPREREQ=NOPREREQ