This is a new feature in version 0.3.4, it required you to have booted FlashLinux from a USB flash key and to have the LiveCD in the drive. Once you have installed (or removed) packages, a reboot is strongly recommended from a speed of operation point of view. In particular, if you install OpenOffice and try to use it immediately, it will be very slow.

A general note on speed;
Probably worth noting that OpenOffice is very slow, mainly because it is build in isolation with it's own packages and libraries. It can take between 20 and 30 seconds to start first time around. (it's faster second time around it the system will cache much of it)  Abiword and Gnumeric will on the other hand, typically start within 4-5 seconds because they rely on libraries already live on the system.

Starting the package manager;
To start the package manager, log in as root and type;

flash_install.sh

The script will try to mount the CD and display a list of optional packages that can be installed or de-installed. If it's not on the list, then at present you can't automatically install or de-install it, although you may do whatever you wish by hand, as long as you know what you're doing.

Packages marked with an "*" are installed, those not marked are available for installation. To add or remove a package, highlight the package using the up and down cursor keys, then mark or unmark the package with the spacebar.

Once you've made your changes, use the left / right cursor keys to select Install/Remove, then press Return.

You can select or de-select any number of packages "in one go", however once you select the "Install/Remove" option, you will be asked to confirm each option individually before your system is modified.