What is the format of data that is saved to a URL from a form? Can I use form data to construct a REST call this way? I need to be able to construct a REST call with input from the user. Does the Form widget help me with this, or do I need to construct it via HTML?
Yes, essentially the Form widget structures a basic HTML form, which then POSTs the inputted data in the standard application/x-www-form-urlencoded data type to the URL specified.
To get a better idea of how this functions, you can create a form in CM1 and publish it out to your server. Then, take a look at the source code of the page to see the structure of the form, and / or you can use dev tools such as Firebug for Firefox or those built into Chrome, toggle over to the Network tab, and submit content through the form to see exactly how the data is being transmitted.
When I create a form, the submit button is disabled, so nothing happens.
<input type="submit" value="Push Here" disabled>
How can I enable the button?
The forms widget, like other DTS powered widgets, will not work when viewed in Preview mode. It will only function when published out to a DTS enabled server environment.