The New and Edit buttons both bring up the same chord editor window, albeit with a slightly different window title and OK button. A box near the bottom of the window displays help messages as you move around the window, so explore its coolness! I think it's pretty intuitive -- it's mostly point and click. If the fret number is 1, the "zero" fret will actually be a nut GIF when the HTML is generated.
Once you have accumulated the right number of chords in the list (about 2-3 if it will be side-by-side with lyrics, up to 4-6 otherwise), click on the HTML button. The generated HTML code will appear in a new document window, from which you can drag and drop the text over to your HTML editor. (If you are using Claris Home Page, go into 'Edit HTML Source' mode, drag the text from Web-a-Chord to your CHP document, then return to 'Edit Page' mode.) The generated HTML is a 2-row by 2*n-column table. Have fun!