if you already rooted and/or have a recovery on your phone, just dl the zip file for the radioactive rom, put it on your sd card, go into recovery, unzip the file in recovery, and it should be installed. after it's installed, reboot, and then your good to go.
if not, (these are not the vids the op is talking bout, but the ones i used and worked for me) watch these to root and put recovery on your phone:
How-To: Root a Samsung Moment with 2.1 Firmware
(you can actually stop following the vid after about 3:55 into the second vid, after he shows you how to put on the recovery.)
then go here :
Radioactive FroYo ROM v1.8.6 **9.2 MFLOP** **Moment-Acclaim Hybrid**
dl the rom, put it on your sd card, turn off phone, go into recover (hold down the volume down + talk +end keys at the same time), etc ( what i wrote above)
hope that helps