Reference
No. The GTD method in NextAction explains what you need, and the five-minute tour gets you started.
To your Inbox. Process it to move it onto a list.
An Area is ongoing and never finishes. A Project has an outcome and ends. See Areas of Focus and Projects.
Yes. See Importing from Nirvana.
Not yet. See Alpha limitations.
See Deleting your data.
See Getting support.