How do I turn notifications ON/OFF for those I am following?

The "Twitter Phone FAQ" says:

====Start of quote====
Can I turn updates on for some people and off for others?

Yes. Set up text preferences for people you follow from the drop down 'following' box on the profile page.

How do I turn a specific person's updates on or off from my phone?

To get a person's updates on your phone, use the commands FOLLOW or ON + username, like this: follow caroline, on caroline

To turn updates off again, send LEAVE or OFF + username, like this. leave crystal, off crystal

You can change notification preferences from the profile pages of everyone you follow.
====End of quote====

I cannot find either "the drop down 'following' box on the profile page" or "notification preferences from the profile pages of everyone you follow".

Where are these? How do I find them? How do I turn notifications ON/OFF for those I am following?

Thanks in advance,

Jim Renkel