Your personal task board. Anything in your head goes in the Inbox; you decide what's a Next Action, what's Waiting on someone else, and what's for Someday.
Get everything out of your head. Drop it in the Inbox — don't think, just dump.
Process each Inbox item: Is it actionable? If yes, what's the next physical action?
Move it to Next Actions, Waiting For (delegated), or Someday/Maybe (not now).
Review your lists weekly. Update what's stale. Trust the system to keep your mind clear.
Pick what to do based on context, time available, energy, and priority. Then do it.