With tarball installation, Apache configuration files will be installed in /usr/local/lemonldap-ng/etc/, else they are in /etc/lemonldap-ng.
You have to include them in Apache main configuration, for example:
include /usr/local/lemonldap-ng/etc/portal-apache2.conf include /usr/local/lemonldap-ng/etc/handler-apache2.conf include /usr/local/lemonldap-ng/etc/manager-apache2.conf include /usr/local/lemonldap-ng/etc/test-apache2.conf
conf.d or sites-available Apache directory.a2ensite manager-apache2.conf a2ensite portal-apache2.conf a2ensite handler-apache2.conf a2ensite test-apache2.conf
You will also need to load some Apache modules:
a2enmod fcgid perl alias rewrite headers