GTD and contexts

I'm having a hard time getting mt GTD groove on. My issues are making my context lists, I don't know where to start and how deep to go with it. I found this awesome article just about this topic and it's helping me figure it out but I still need help. Now I can't afford to have David Allen drop over to my house for a quick lesson so I'll ask all of you reading this.
I think I need:
@online
@offline
@phone
@errand

Then I need agenda lists for people I deal with:
@sean
@dan
@"anybody I deal with"

My biggest question is are these things email folders/labels or are they notes that I actually type in myself? Currently I'm using gmail online and I'm now use to using my email as my action items. Where I keep them unread if I need to do something, but that doesn't help me in knowing if I need to use computer, email, phone, or even how long it's going to take.

Any help from the crowd would be awesome. Once I think I have it and I sit down to start building it I get lost.

Sphere: Related Content