[Plugin: DW Promobar] Create e-mail subscribe box?

How do I put a box into the bar that will allow visitors to write their e-mail addresses in and press the “Subscribe” button?

Also, when they press the “Subscribe” button, where should the button link to so that it would save their address to a database for weekly newsletters? Should I combine this with a newsletter plugin?

Would I have to enter code?

If so, what would the code to do that be? I’m not experienced with HTML or CSS at all.

Link to my site: allfitnesshelp.com