Don't see how you're confused when it's all clear
In OU, you can't user ubers.
You can't have those abilities.
You can't use Soul Dew (as if you could obtain it anyway)
You can't use a pokemon with Drizzle and a pokemon with Swift Swim (not that it matters because there's only one pokemon used)
this is a bit more up to date but yeah
http://www.smogon.com/xyhub/tiers
My FC is on my profile in the information section