There are six command buttons and four radio buttons in the upper section which handle creating new documents, copying them, saving, etc. Here is a rundown on what each does:
The New button creates a completely new document with all fields except the order date cleared. If you have unsaved changes in another document, you will be prompted to save them first.
The Copy button creates a new document with all fields filled in just as they are. This is a big time saver if you regularly write similar proposals, need to write the same thing for many different customers, etc. Just create the first one (or select a previously saved document), and copy it!
The Wipe button has the same effect as New, except does not assign a new number.
Preview / Print displays the document as-is in the preview / print form.
The Save button saves all changes to the document you are working on, and also to the sold-to and ship-to addresses (if changed or new).
The Help button displays this help file (same as pressing the F1 key).
Finally, the five radio buttons control what type of document to output: Proposal, Acknowledgement, Invoice, or Receipt, plus documents can be tagged as "trash" (use "trash" for proposals that never went anywhere, unpaid invoices you've given up on, etc.)
All documents that you save can be pulled up later for editing (changing from proposal to invoice, for example), re-printing and/or copying. Click on the Proposals - Invoices bar (just below the Total field) to see the list. Click the same bar (which now says "Stock Items List"), or double-click any document to return to normal display.