No, we're only flashing the kernel here, not the rootfs.

-k tells flasher-3.0 where the kernel image is (this is the zImage you downloaded from fanoush's website).
-f tells flasher-3.0 to flash.
-R tells flasher-3.0 to have the device reboot after flashing.

1. Turn your device off, plug it in with USB.
2. Run the flasher-3.0 command.
3. Turn on your device while holding down the Home key.
4. Let it flash, let it reboot, then remove the USB.

Now you need to get the blset script installed so you can change the brightness levels. Grab it from fanoush's site, stick it in /usr/local/bin (vi /usr/local/bin/blset and paste from the web browser or wget -O /usr/local/bin/blset http://fanoush.wz.cz/maemo/blset), chmod it 755, and test it (not sure if /usr/local/bin is in the search path by default, so you might just copy it over to /usr/bin).

blset [0-127] will change the backlight level of the current software level (the one selected in the statusbar applet). You can change the values of all levels, but as they reset on restart, there's not much point unless you set something up to change them for you on every reboot. Since I pretty much just use it for reading at brightness level 1 at night, I just use blset 1 while on the lowest statusbar applet level.