How can I avoid iCloud in El Capitan?

I just updated from Yosemite to El Capitan. I have never used iCloud and don't want to. In the initial El Capitan setup it asks for my Apple ID to use for a set of features including iCloud that I don't want to use, but also FaceTime, iTunes, and App Store that I do want to use. I "skipped this step" rather than enter my Apple ID and password. How can I use my Apple ID for just those other features? I tried System Preferences...iCloud hoping to find a "disable" or "don't use iCloud" option but can't find one. I tried launching FaceTime and iTunes but when it asks for my Apple ID it's not clear that it is just for that app not for iCloud too so I've hesitated to log in to those. Thanks.