Implementation Questions - CONTEXT?!

I've been trying to set up a GTD system for a while and just keep hitting walls trying to figure out what to do.

Collecting isn't a problem, but processing is. I can set up projects, determine next actions, and so on. The big problem I hit is context. Like many of us geeks, an @computer context doesn't work.

Let me explain my life situation. I'm a college student, so a @School context would be useful (or will, when summer break ends), but I don't know what to do for other projects and things. I do web design, am teaching myself PHP, and also write - all things that have to be done @Computer - but that's most of my life. Standard geek problem. How do I contextualize stuff like "Write PHP script to insert data in DB"?

I'm so lost. A Global NA list is just too much. It becomes monstrous, and overwhelming. It was overwhelming to just look at my collection list when I started - and I still haven't finished processing it.

HELP!

Okay, I think I understand....

Okay, I think I understand. Here's my context list now after a bit of brainstorming

@School
@Homework
@Home
@Errands
@Work
@Calls
@Design
@Computer (General)
@Writing
@Programming
@Meta (System Maintance, basically, like checking my tickler, and stuff.)
@Nocontext (Anything I can just do at any time.)

So, now that I have this, I can take my next actions and contextualize them into little sublists so I know what to do next for whichever project I feel like doing.

I think I get it, but I'm not sure. I've got to replace my copy of The Book today (left it in my bag and my cat whizzed on it,) so I'll re-read it and see what David has to say about where to go from here.