How do I implement the 6-level model in my GTD set-up?

[TesTeq]

I'm new at this and am still getting comfortable using the GTD system, but it seems like differentiating between runway, 10k, 20k, 30k, 40k and 50k tasks is difficult for me.

What do you mean by 10k, 20k, 30k, 40k and 50k tasks?