To install tenshi:

Add a user and group named tenshi.

As root:

$ make install

Edit the config in /etc/tenshi/tenshi.conf

Please Read The Fine Manual once through before running tenshi to make sure you
understand whats going on and that you satisfy the REQUIREMENTS section.

Copy the tenshi.<os>-init to wherever your init scripts live. Currently we only
have init scripts for Gentoo, Debian and Solaris but we would be very happy to
accept init scripts for other operating systems.

Add tenshi to whatever run levels you need it to run in.

To start run as root:

$ /etc/init.d/tenshi start

(or whatever is appropriate for your OS, again, comments welcome :) )

Thats it!

tenshi should now email you reports as per your configuration.