> write out each mind dumped item on a sheet of paper and make a
> folder for it
I believe Allen recommends single sheets when doing your first mind sweep. This helps manage the possible overwhelm of your start. However, feel free to use multiple lines on a single page (or pages) for future brain dumps. You'll be processing them then crossing them out within 24 hours or so.
Make a folder for a project only if you have supporting materials, plans, printed documents, etc. If there's no paper, no need to make a folder. However, you *will* need to add an entry for the new project on your master Projects list. Katherine has good suggestions in her reply.
If "Plan a trip to NYC" is a Someday/Maybe project, then add it to that list. Note that I recommend using a *folder* for S/M, as very often I get printed matter in this category, and it's easier to simply file it. I have a mixture of items like that and lists of things that come up, but which have no paper artifact.
> For a true "project" that takes multiple action steps to complete,
> should I have a folder for the project itself AND a folder for
> Project Support Materials, or just have a "Projects" list and just
> one folder, which holds Project Support Materials?
The former - every project needs its own dedicated folder, again, only if it has associated paper. There *is* a very useful idea of an "Action Support" folder, which is for in-process actions that don't have a project or folder. For example, bills you haven't paid yet, or receipts that you're waiting for. But don't use a large "catch all" folder for all projects.