It should be started from within Live CD, Network Boot or from any bootable media, other then Your system disk. It fully supports software RAID. You can change defaults and most settings with command line options and configuration variables. All settings if not defined in config file or as command line options, will be set to it's defaults either as constant values or evaluated from running system.
By default it chooses largest disk for installation. If there are more then one such disk of the same size, it makes RAID array. Partitioning scheme supports separate partition for /boot, and separate logical volumes for root filesystem, /usr, /var, /tmp and /home. Also there are option to install system into single pre-mount point. In this case partitioning and mounting every part leave on Your own.
This script installs only bit more packages then base system includes. The main purpose is to get bootable system. After booting new system You can install everything what You want.
You can get bootable system including ssh server in few minutes. You save lot of time on preparing of disk, assemble RAID array, network configuration and other things. I believe default settings are suitable and good enough in most cases. If not, You can define Your own defaults in config file for next installations. You don't need big and complex installation system on dedicated CD. It is just single shell script, that You can use anywhere. I like use it for set up new servers remotely.