Well... The best advice to give to say that you should scheck out a few tutorials before trying anything complicated.
That being said, what you're trying to do is not complicated (much)...
Open the CS, locate the Object Window. right click on the tab that says "enchantment" and select new.
You'll need to create a unique ID for the enchantment, so you might enter something with your initials at the front, like "JS_ShockResist". You will next need to select whether you want this to be a constant effect or used when cast. Click the dropdown and choose.
Lower under "effects" click the dropdown, choose the spell effect you want. set the other fields according to what you want ... self, duration, magnitude. you might want to untic the auto calc because a 100% is going to have a high cost and save it.
Then go to clothing, find the ring you want, change the ID to something unique. look for the enchantment field, you'll probably want to set it to at least 1200 (which gives 120 in game) then click the drop down for enchanting, find the enchantment you created, and select it. Save.
Click on save on the tool bar or under file and save your new mod with a name of your choosing... and you're done (other than things like cleaning the mod and so forth, for which you might want those tutorials... and a utility or two).