All of those scripts are already in the very first post.
attached to the first post has the Main Menu Melody script and the Skill and Equip Menus. You can just look in there to see where to put them in the Script Editor. As a general rule, there isn't a whole lot of magic to it - You just paste them above Main and below Materials. Order only becomes an issue when you are using many scripts, but that depends on the content of the individual scripts. You can see the order for the Melody scripts from the demo. The Final Fantasy 13 Menu
is under the Shanghai heading in the first post and needs to be put BELOW Main Menu Melody, but ABOVE Main.
So, absent any other scripts, the order would be:
YEM Equipment Overhaul
YEM Main Menu Melody
SSS FF13 Menu
YEM Skill Overhaul
I actually don't think there needs to be a special order for the Skill and Equipment scripts, but I am just going on the demo. I don't really have time to examine the scripts.